cap it so we don't cry

Merge remote-tracking branch 'sunnypilot/sunnypilot/master' into hkg-angle-steering-2025-wee
modeld_v2: big to small model fallback (#1974 )
2026-09-02 08:23:43 +08:00 · 2026-09-01 00:35:09 -04:00 · 2026-09-01 00:16:21 -04:00 · 2026-09-01 00:15:23 -04:00 · 2026-08-30 16:20:16 -04:00 · 2026-08-28 12:58:26 -04:00
55 changed files with 2964 additions and 387 deletions
@@ -2,5 +2,6 @@ Wen
 REGIST
 PullRequest
 cancelled
+indeces
 FOF
 NoO
@@ -8,13 +8,13 @@ on:
        required: true
        type: string
      target_hardware:
-        description: 'Hardware target to compile for (qcom or usbgpu)'
+        description: 'Hardware target to compile for (qcom or chestnut)'
        required: true
        type: choice
        default: 'qcom'
        options:
          - qcom
-          - usbgpu
+          - chestnut
      hf_repo:
        description: 'Hugging Face dataset repository'
        required: false
@@ -59,7 +59,7 @@ jobs:
        id: get-json
        run: |
          cd docs/docs
-          PREFIX="driving_models_${{ inputs.target_hardware == 'usbgpu' && 'usbgpu_' || '' }}v"
+          PREFIX="driving_models_${{ inputs.target_hardware == 'chestnut' && 'chestnut_' || '' }}v"
          latest=$(ls ${PREFIX}*.json | sed -E "s/${PREFIX}([0-9]+)\.json/\1/" | sort -n | tail -1)
          next=$((latest+1))
          json_file="${PREFIX}${next}.json"
@@ -176,7 +176,7 @@ jobs:
  build_big_model:
    needs: resolve
    if: ${{ inputs.target == 'big' }}
-    runs-on: [self-hosted, usbgpu]
+    runs-on: [self-hosted, chestnut]
    env:
      BIG_ONNX: openpilot/selfdrive/modeld/models/big_driving_supercombo.onnx
      BIG_PKL: openpilot/selfdrive/modeld/models/big_driving_tinygrad.pkl
@@ -30,7 +30,7 @@ on:
        type: boolean
        default: true
      target_hardware:
-        description: 'Hardware target to compile for (qcom or usbgpu)'
+        description: 'Hardware target to compile for (qcom or chestnut)'
        required: false
        type: string
        default: 'qcom'
@@ -101,7 +101,7 @@ on:
        default: 'qcom'
        options:
          - qcom
-          - usbgpu
+          - chestnut
      hf_repo:
        description: 'Hugging Face dataset repository'
        required: false
@@ -109,7 +109,7 @@ on:
        default: 'sunnypilot/sunnypilot_models_v1'
 env:
  RECOMPILED_DIR: recompiled${{ inputs.recompiled_dir }}
-  JSON_FILE: docs/docs/driving_models_${{ inputs.target_hardware == 'usbgpu' && 'usbgpu_v' || 'v' }}${{ inputs.json_version }}.json
+  JSON_FILE: docs/docs/driving_models_${{ inputs.target_hardware == 'chestnut' && 'chestnut_v' || 'v' }}${{ inputs.json_version }}.json

 jobs:
  build_model:
@@ -31,7 +31,7 @@ on:
        type: string
        default: ''
      target_hardware:
-        description: 'Hardware target to compile for (qcom or usbgpu)'
+        description: 'Hardware target to compile for (qcom or chestnut)'
        required: false
        type: string
        default: 'qcom'
@@ -57,7 +57,7 @@ on:
        type: choice
        options:
          - qcom
-          - usbgpu
+          - chestnut
        default: 'qcom'


@@ -102,7 +102,7 @@ jobs:
          cat $GITHUB_OUTPUT
      - run: |
          cd ${{ github.workspace }}/openpilot/openpilot
-          if [ "${{ inputs.target_hardware }}" != "usbgpu" ]; then
+          if [ "${{ inputs.target_hardware }}" != "chestnut" ]; then
            git lfs pull -X "**/selfdrive/modeld/models/big_*.onnx,**/selfdrive/modeld/models/dmonitoring_*.onnx"
            rm -f selfdrive/modeld/models/big_*.onnx selfdrive/modeld/models/dmonitoring_*.onnx
          else
@@ -121,7 +121,7 @@ jobs:
          if-no-files-found: error

  build_model:
-    runs-on: [self-hosted, usbgpu]
+    runs-on: [self-hosted, chestnut]
    needs: get_model
    env:
      MODEL_NAME: ${{ inputs.custom_name || inputs.upstream_branch }} (${{ needs.get_model.outputs.model_date }})
@@ -185,9 +185,9 @@ jobs:
          CAMERA_RES=$(python3 -c "from openpilot.common.transformations.camera import _ar_ox_fisheye as a, _os_fisheye as o; print(f'{a.width}x{a.height} {o.width}x{o.height}')")

          TG_FLAGS_QCOM="DEV=QCOM IMAGE=1 FLOAT16=1 NOLOCALS=1 JIT_BATCH_SIZE=0 OPENPILOT_HACKS=1"
-          if [ "${{ inputs.target_hardware }}" == "usbgpu" ]; then
-            echo "USBGPU build"
-            export USBGPU=1
+          if [ "${{ inputs.target_hardware }}" == "chestnut" ]; then
+            echo "CHESTNUT build"
+            export CHESTNUT=1
            TG_FLAGS="DEBUG=1 DEV=USB+AMD:LLVM WARP_DEV=QCOM FLOAT16=1 JIT_BATCH_SIZE=0 GMMU=0 TC_OPT=2"
            OUTPUT_PKL="${{ env.MODELS_DIR }}/big_driving_tinygrad.pkl"
          else
@@ -21,5 +21,12 @@
        </clean>
      </configuration>
    </target>
+    <target id="f2590b2b-9b93-49f9-8510-da3f3724a2ae" name="replay" defaultType="TOOL">
+      <configuration id="d475264f-6f4c-4092-9b4e-6773309f38b7" name="replay" toolchainName="Default">
+        <build type="TOOL">
+          <tool actionId="Tool_External Tools_uv build tools replay" />
+        </build>
+      </configuration>
+    </target>
  </component>
 </project>
@@ -20,4 +20,11 @@
      <option name="WORKING_DIRECTORY" value="$ProjectFileDir$" />
    </exec>
  </tool>
+  <tool name="uv build tools replay" showInMainMenu="false" showInEditor="false" showInProject="false" showInSearchPopup="false" disabled="false" useConsole="true" showConsoleOnStdOut="false" showConsoleOnStdErr="false" synchronizeAfterRun="true">
+    <exec>
+      <option name="COMMAND" value="bash" />
+      <option name="PARAMETERS" value="-c &quot;source .venv/bin/activate &amp;&amp; scons -u -j$(nproc) tools/replay/&quot;" />
+      <option name="WORKING_DIRECTORY" value="$ProjectFileDir$" />
+    </exec>
+  </tool>
 </toolSet>
@@ -1,5 +1,5 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="Build Debug" type="CLionExternalRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" WORKING_DIR="file://$ProjectFileDir$/selfdrive/ui" PASS_PARENT_ENVS_2="true" PROJECT_NAME="sunnypilot" TARGET_NAME="uv Scons Build Debug" CONFIG_NAME="uv Scons Build Debug" RUN_PATH="ui">
+  <configuration default="false" name="Build Debug" type="CLionExternalRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="false" WORKING_DIR="file://$ProjectFileDir$/selfdrive/ui" PASS_PARENT_ENVS_2="true" PROJECT_NAME="openpilot-special" TARGET_NAME="uv Scons Build Debug" CONFIG_NAME="uv Scons Build Debug" RUN_PATH="ui">
    <envs>
      <env name="QT_DBL_CLICK_DIST" value="150" />
    </envs>
@@ -0,0 +1,27 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Debug Route Controls" type="PythonConfigurationType" factoryName="Python">
+    <module name="openpilot-special" />
+    <option name="ENV_FILES" value="" />
+    <option name="INTERPRETER_OPTIONS" value="" />
+    <option name="PARENT_ENVS" value="true" />
+    <envs>
+      <env name="PYTHONUNBUFFERED" value="1" />
+      <env name="FINGERPRINT" value="KIA_EV9" />
+      <env name="SKIP_FW_QUERY" value="1" />
+    </envs>
+    <option name="SDK_HOME" value="" />
+    <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$/selfdrive/car" />
+    <option name="IS_MODULE_SDK" value="true" />
+    <option name="ADD_CONTENT_ROOTS" value="true" />
+    <option name="ADD_SOURCE_ROOTS" value="true" />
+    <EXTENSION ID="PythonCoverageRunConfigurationExtension" runner="coverage.py" />
+    <option name="SCRIPT_NAME" value="$PROJECT_DIR$/selfdrive/car/card.py" />
+    <option name="PARAMETERS" value="" />
+    <option name="SHOW_COMMAND_LINE" value="false" />
+    <option name="EMULATE_TERMINAL" value="true" />
+    <option name="MODULE_MODE" value="false" />
+    <option name="REDIRECT_INPUT" value="false" />
+    <option name="INPUT_FILE" value="" />
+    <method v="2" />
+  </configuration>
+</component>
@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Replay for controls + ui" type="Multirun" separateTabs="false" reuseTabsWithFailures="false" startOneByOne="true" markFailedProcess="true" hideSuccessProcess="false" delayTime="0.0">
+    <runConfiguration name="replay for controls" type="Native Application" />
+    <runConfiguration name="Build Debug" type="Custom Build Application" />
+    <method v="2" />
+  </configuration>
+</component>
@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="replay for controls" type="CLionNativeAppRunConfigurationType" focusToolWindowBeforeRun="true" PROGRAM_PARAMS="&quot;$Prompt$&quot; --block &quot;sendcan,carState,carParams,carOutput,liveTracks,carParamsSP,carStateSP,bookmarkButton&quot;" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" EMULATE_TERMINAL="true" WORKING_DIR="file://$ProjectFileDir$/tools/replay" PASS_PARENT_ENVS_2="true" PROJECT_NAME="openpilot-special" TARGET_NAME="replay" CONFIG_NAME="replay" version="1" RUN_PATH="replay">
+    <method v="2">
+      <option name="CLION.COMPOUND.BUILD" enabled="true" />
+    </method>
+  </configuration>
+</component>
@@ -353,6 +353,7 @@ struct OnroadEventSP @0xda96579883444c35 {
    speedLimitPending @22;
    e2eChime @23;
    laneChangeRoadEdge @24;
+    bigModelReady @25;
  }
 }

@@ -130,8 +130,8 @@ inline static std::unordered_map<std::string, ParamKeyAttributes> keys = {
    {"UpdaterLastFetchTime", {PERSISTENT, TIME}},
    {"UptimeOffroad", {PERSISTENT, FLOAT, "0.0"}},
    {"UptimeOnroad", {PERSISTENT, FLOAT, "0.0"}},
-    {"UsbGpuActive", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION | CLEAR_ON_IGNITION_ON, BOOL}},
-    {"UsbGpuLoading", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION | CLEAR_ON_IGNITION_ON, BOOL}},
+    {"ChestnutActive", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION | CLEAR_ON_IGNITION_ON, BOOL}},
+    {"ChestnutLoading", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION | CLEAR_ON_IGNITION_ON, BOOL}},
    {"Version", {PERSISTENT, STRING}},

    // --- sunnypilot params --- //
@@ -195,15 +195,16 @@ inline static std::unordered_map<std::string, ParamKeyAttributes> keys = {

    // Model Manager params
    {"ModelManager_ActiveBundle", {PERSISTENT, JSON}},
-    {"ModelManager_ActiveBundleUSBGPU", {PERSISTENT, JSON}},
+    {"ModelManager_ActiveBundleUSBGPU", {PERSISTENT, JSON}}, //TODO-SP: kept for migration, remove on next sync?
+    {"ModelManager_ActiveBundleChestnut", {PERSISTENT, JSON}},
    {"ModelManager_ActiveJson", {CLEAR_ON_MANAGER_START, JSON}},
    {"ModelManager_ClearCache", {CLEAR_ON_MANAGER_START, BOOL}},
    {"ModelManager_DownloadRef", {CLEAR_ON_MANAGER_START | CLEAR_ON_ONROAD_TRANSITION, STRING}},
    {"ModelManager_Favs", {PERSISTENT | BACKUP, STRING}},
    {"ModelManager_LastSyncTime", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION, INT, "0"}},
-    {"ModelManager_LastSyncTime_USBGPU", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION, INT, "0"}},
+    {"ModelManager_LastSyncTime_Chestnut", {CLEAR_ON_MANAGER_START | CLEAR_ON_OFFROAD_TRANSITION, INT, "0"}},
    {"ModelManager_ModelsCache", {PERSISTENT | BACKUP, JSON}},
-    {"ModelManager_ModelsCache_USBGPU", {PERSISTENT | BACKUP, JSON}},
+    {"ModelManager_ModelsCache_Chestnut", {PERSISTENT | BACKUP, JSON}},

    // Neural Network Lateral Control
    {"NeuralNetworkLateralControl", {PERSISTENT | BACKUP, BOOL, "0"}},
@@ -37,6 +37,8 @@ SP_BRANCH_MIGRATIONS = {
  ("tizi", "release3-staging"): "release-tizi-staging",
  ("mici", "release3"): "release-mici",
  ("mici", "release3-staging"): "release-mici-staging",
+  ("tici", "hkg-angle-steering-2025"): "hkg-angle-steering-2025-tici",
+  ("tici", "hkg-angle-steering-2025-prebuilt"): "hkg-angle-steering-2025-tici-prebuilt"
 }

 BUILD_METADATA_FILENAME = "build.json"
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:845c40ff0d37612e8f2f482a36845744b5ae91ce2fcfc8117990d7d278b59820
+size 13079
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:8a8c5fece2a1c7587feb41cbe04c6aee08e768ecd9b5d00da6af9832a4ccc842
-size 2034
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:7409c53d7c72681c24982fd83b56ce70f80797c9c0f936d9296a5c18557ac472
-size 7279
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:58bd6155433f623b1f75d134bd8ca4745d9aa71f6767eb807cdbcf7deb3089a1
-size 10876
@@ -7,7 +7,7 @@ from openpilot.common.file_chunker import chunk_file, get_chunk_targets, get_exi
 from openpilot.common.transformations.camera import _ar_ox_fisheye, _os_fisheye
 from openpilot.common.transformations.model import MEDMODEL_INPUT_SIZE, DM_INPUT_SIZE
 from openpilot.selfdrive.modeld.constants import ModelConstants
-from openpilot.selfdrive.modeld.helpers import TG_INPUT_DEVICES_PATH, usbgpu_present, modeld_pkl_path
+from openpilot.selfdrive.modeld.helpers import TG_INPUT_DEVICES_PATH, chestnut_present, modeld_pkl_path


 CAMERA_CONFIGS = [
@@ -36,18 +36,18 @@ else:
 tg_devices = { # which device to put jit inputs to at runtime
  'openpilot.selfdrive.modeld.modeld': {
    'default': {'WARP_DEV': tg_backend, 'QUEUE_DEV': tg_backend},
-    'usbgpu': {'WARP_DEV': tg_backend, 'QUEUE_DEV': 'AMD'}
+    'chestnut': {'WARP_DEV': tg_backend, 'QUEUE_DEV': 'AMD'}
  },
  'openpilot.selfdrive.modeld.dmonitoringmodeld': {
    'default': {'DEV': tg_backend}
  },
 }

-USBGPU = usbgpu_present()
-if USBGPU:
-  usbgpu_tg_flags = f'DEBUG=2 DEV=USB+AMD:LLVM WARP_DEV={tg_backend} FLOAT16=1 JIT_BATCH_SIZE=0 GMMU=0 TC_OPT=2'
+CHESTNUT = chestnut_present()
+if CHESTNUT:
+  chestnut_tg_flags = f'DEBUG=2 DEV=USB+AMD:LLVM WARP_DEV={tg_backend} FLOAT16=1 JIT_BATCH_SIZE=0 GMMU=0 TC_OPT=2'
  # the USB+AMD GPU takes an exclusive flock; serialize all targets that touch it
-  usbgpu_lock = File("models/.usb_gpu.lock").abspath
+  chestnut_lock = File("models/.chestnut.lock").abspath

 def write_tg_devices(target, source, env):
  with open(str(target[0]), "w") as f:
@@ -74,10 +74,10 @@ model_w, model_h = MEDMODEL_INPUT_SIZE
 frame_skip = ModelConstants.MODEL_RUN_FREQ // ModelConstants.MODEL_CONTEXT_FREQ

 if not os.getenv('SKIP_TINYGRAD_COMPILE'):
-  for usbgpu in [False, True] if USBGPU else [False]:
-    target_pkl_path = File(modeld_pkl_path(usbgpu)).abspath
-    # BIG_INTO_SMALL=1 builds the default target from the big model, e.g. to test it without a USB GPU
-    file_prefix, cmd_flags = ('big_', usbgpu_tg_flags) if usbgpu else ('big_' if os.getenv('BIG_INTO_SMALL') else '', tg_flags)
+  for chestnut in [False, True] if CHESTNUT else [False]:
+    target_pkl_path = File(modeld_pkl_path(chestnut)).abspath
+    # BIG_INTO_SMALL=1 builds the default target from the big model, e.g. to test it without a chestnut
+    file_prefix, cmd_flags = ('big_', chestnut_tg_flags) if chestnut else ('big_' if os.getenv('BIG_INTO_SMALL') else '', tg_flags)
    driving_onnx_deps = get_existing_chunks(File(f"models/{file_prefix}driving_supercombo.onnx").abspath)
    camera_res_args = ' '.join(f'{cw}x{ch}' for cw, ch in CAMERA_CONFIGS)
    # CPU 7 is isolated with isolcpus on AGNOS, so explicitly pin the compiler to it.
@@ -104,14 +104,14 @@ if not os.getenv('SKIP_TINYGRAD_COMPILE'):
      chunk_file(pkl, chunks)
    def do_chunk(target, source, env, pkl=target_pkl_path, chunks=chunk_targets):
      chunk_file(pkl, chunks)
-    actions = Action(do_compile, "  [USBGPU] $TARGET") if usbgpu else [cmd, Action(do_chunk, "  [CHUNK] $TARGET")]
+    actions = Action(do_compile, "  [CHESTNUT] $TARGET") if chestnut else [cmd, Action(do_chunk, "  [CHUNK] $TARGET")]
    node = lenv.Command(
      chunk_targets,
      tinygrad_files + compile_modeld_script + driving_onnx_deps + [Value(chunk_targets), chunker_file],
      actions,
    )
-    if usbgpu:
-      lenv.SideEffect(usbgpu_lock, node)
+    if chestnut:
+      lenv.SideEffect(chestnut_lock, node)

 # get model metadata
 fn = File(f"models/dmonitoring_model").abspath
@@ -29,7 +29,7 @@ class ModelState:
  output: np.ndarray

  def __init__(self, cam_w: int, cam_h: int):
-    self.DEV = get_tg_input_devices(PROCESS_NAME, usbgpu=False)['DEV']
+    self.DEV = get_tg_input_devices(PROCESS_NAME, chestnut=False)['DEV']
    with open(METADATA_PATH, 'rb') as f:
      model_metadata = pickle.load(f)
      self.input_shapes = model_metadata['input_shapes']
@@ -13,12 +13,12 @@ MODELS_DIR = Path(__file__).resolve().parent / 'models'
 TG_INPUT_DEVICES_PATH = MODELS_DIR / 'tg_input_devices.json'


-def get_tg_input_devices(process_name: str, usbgpu: bool):
+def get_tg_input_devices(process_name: str, chestnut: bool):
  with open(TG_INPUT_DEVICES_PATH) as f:
-    return json.load(f)[process_name]['default' if not usbgpu else 'usbgpu']
+    return json.load(f)[process_name]['default' if not chestnut else 'chestnut']

-def modeld_pkl_path(usbgpu: bool):
-  prefix = 'big_' if usbgpu else ''
+def modeld_pkl_path(chestnut: bool):
+  prefix = 'big_' if chestnut else ''
  return MODELS_DIR / f'{prefix}driving_tinygrad.pkl'

 def dump_oob(obj, f):
@@ -45,7 +45,7 @@ def load_oob(f):
      yield pb
  return pickle.load(io.BytesIO(opcodes), buffers=buffers())

-def usbgpu_present() -> bool:
+def chestnut_present() -> bool:
  for d in USB_DEVICES_PATH.glob("*"):
    try:
      usb_id = (int((d / "idVendor").read_text(), 16), int((d / "idProduct").read_text(), 16))
@@ -56,5 +56,5 @@ def usbgpu_present() -> bool:
      pass
  return False

-def usbgpu_compiled() -> bool:
-  return Path(get_manifest_path(modeld_pkl_path(usbgpu=True))).is_file()
+def chestnut_compiled() -> bool:
+  return Path(get_manifest_path(modeld_pkl_path(chestnut=True))).is_file()
@@ -1,7 +1,9 @@
 #!/usr/bin/env python3
+from collections.abc import Callable
+import ctypes
 from functools import cached_property
 import os
-os.environ['GMMU'] = '0' # for usbgpu fast loading, noop for qcom
+os.environ['GMMU'] = '0' # for chestnut fast loading, noop for qcom
 from tinygrad.tensor import Tensor
 from tinygrad.device import Device
 import struct
@@ -30,7 +32,7 @@ from openpilot.selfdrive.modeld.compile_modeld import make_input_queues, WARP_IN
 from openpilot.selfdrive.modeld.fill_model_msg import fill_model_msg, fill_driving_model_data, fill_pose_msg, PublishState
 from openpilot.common.file_chunker import open_file_chunked
 from openpilot.selfdrive.modeld.constants import ModelConstants, Plan
-from openpilot.selfdrive.modeld.helpers import usbgpu_present, usbgpu_compiled, modeld_pkl_path, get_tg_input_devices, load_oob
+from openpilot.selfdrive.modeld.helpers import chestnut_present, chestnut_compiled, modeld_pkl_path, get_tg_input_devices, load_oob

 from openpilot.sunnypilot.livedelay.helpers import get_lat_delay
 from openpilot.sunnypilot.modeld_v2.modeld_base import ModelStateBase
@@ -94,8 +96,10 @@ class ChestnutState:
    if self.big and "AMD" in Device._opened_devices and self.sends % 100 == 1:
      try:
        smu = Device["AMD"].iface.dev_impl.smu
+        metrics_t = smu.smu_mod.SmuMetricsExternal_t
        smu._send_msg(smu.smu_mod.PPSMC_MSG_TransferTableSmu2Dram, smu.smu_mod.TABLE_SMU_METRICS, timeout=100)
-        metrics = smu.read_table(smu.smu_mod.SmuMetricsExternal_t, smu.smu_mod.TABLE_SMU_METRICS).SmuMetrics
+        metrics_buf = bytearray(smu.adev.vram.view(smu.driver_table_paddr, ctypes.sizeof(metrics_t))[:])
+        metrics = metrics_t.from_buffer(metrics_buf).SmuMetrics
        self.metrics = {'tempC': metrics.AvgTemperature[smu.smu_mod.TEMP_HOTSPOT],
                        'memoryTempC': metrics.AvgTemperature[smu.smu_mod.TEMP_MEM],
                        'powerDrawW': metrics.AverageSocketPower,
@@ -141,18 +145,18 @@ class FrameMeta:
 class ModelState(ModelStateBase):
  prev_desire: np.ndarray  # for tracking the rising edge of the pulse

-  def __init__(self, cam_w: int, cam_h: int, usbgpu: bool):
+  def __init__(self, cam_w: int, cam_h: int, chestnut: bool):
    ModelStateBase.__init__(self)
-    input_devices = get_tg_input_devices(PROCESS_NAME, usbgpu)
+    input_devices = get_tg_input_devices(PROCESS_NAME, chestnut)
    self.WARP_DEV, self.QUEUE_DEV = input_devices['WARP_DEV'], input_devices['QUEUE_DEV']
-    jits = load_oob(open_file_chunked(modeld_pkl_path(usbgpu)))
+    jits = load_oob(open_file_chunked(modeld_pkl_path(chestnut)))
    metadata = jits['metadata']
    self.input_shapes = metadata['input_shapes']
    self.vision_input_names = [k for k in self.input_shapes if 'img' in k]
    self.output_slices = metadata['output_slices']

    self.prev_desire = np.zeros(ModelConstants.DESIRE_LEN, dtype=np.float32)
-    self.usbgpu = usbgpu
+    self.chestnut = chestnut

    self.frame_skip = ModelConstants.MODEL_RUN_FREQ // ModelConstants.MODEL_CONTEXT_FREQ
    self.input_queues, self.npy = make_input_queues(self.input_shapes, self.frame_skip, device=self.QUEUE_DEV)
@@ -168,7 +172,7 @@ class ModelState(ModelStateBase):
    return parsed_model_outputs

  def run(self, bufs: dict[str, VisionBuf], transforms: dict[str, np.ndarray],
-          inputs: dict[str, np.ndarray]) -> dict[str, np.ndarray] | None:
+          inputs: dict[str, np.ndarray], after_enqueue: Callable[[], None] | None = None) -> dict[str, np.ndarray]:
    for key in bufs.keys():
      ptr = np.frombuffer(bufs[key].data, dtype=np.uint8).ctypes.data
      yuv_size = self.frame_buf_params[key][3]
@@ -192,11 +196,11 @@ class ModelState(ModelStateBase):
    outs, = self.run_policy(
      **{k: self.input_queues[k] for k in POLICY_INPUTS if k in self.input_queues}, warped=warped
    )
+    if after_enqueue is not None:
+      after_enqueue()
    model_output = outs.numpy()[0]
-    if self.usbgpu and not np.all(np.isfinite(model_output)):
-      # TODO remove with prev_feat
-      cloudlog.error("model output not finite, dropping frame")
-      return None
+    if self.chestnut and not np.all(np.isfinite(model_output)):
+      raise RuntimeError("model output not finite")
    outputs_dict = self.parser.parse_outputs(self.slice_outputs(model_output, self.output_slices))
    self.npy['prev_feat'][:] = model_output[self.output_slices['hidden_state']]

@@ -218,12 +222,12 @@ class ModelState(ModelStateBase):
 def main(demo=False):
  cloudlog.warning("modeld init")

-  USBGPU = usbgpu_present() and usbgpu_compiled()
-  if USBGPU:
+  CHESTNUT = chestnut_present() and chestnut_compiled()
+  if CHESTNUT:
    os.environ['HCQDEV_WAIT_TIMEOUT_MS'] = '3000'
  params = Params()
-  params.put_bool("UsbGpuLoading", USBGPU)
-  params.remove("UsbGpuActive")
+  params.put_bool("ChestnutLoading", CHESTNUT)
+  params.remove("ChestnutActive")

  config_realtime_process(7, 54)

@@ -253,7 +257,7 @@ def main(demo=False):
  st = time.monotonic()
  cloudlog.warning("loading model")
  model = None
-  if USBGPU:
+  if CHESTNUT:
    big_model = None
    def load_big():
      nonlocal big_model
@@ -267,23 +271,23 @@ def main(demo=False):
    loader.start()
    loader.join(BIG_MODEL_TIMEOUT)
    model = big_model
-    params.put_bool("UsbGpuActive", model is not None)
+    params.put_bool("ChestnutActive", model is not None)

-  small_model = ModelState(vipc_client_main.width, vipc_client_main.height, False) if model is None or USBGPU else None
+  small_model = ModelState(vipc_client_main.width, vipc_client_main.height, False) if model is None or CHESTNUT else None
  if model is None:
    model = small_model
-  params.put_bool("UsbGpuLoading", False)
+  params.put_bool("ChestnutLoading", False)
  assert model is not None
  cloudlog.warning(f"models loaded in {time.monotonic() - st:.1f}s, modeld starting")

  # messaging
-  pub_socks = ["modelV2", "drivingModelData", "cameraOdometry", "modelDataV2SP"] + (["chestnutState"] if USBGPU else [])
+  pub_socks = ["modelV2", "drivingModelData", "cameraOdometry", "modelDataV2SP"] + (["chestnutState"] if CHESTNUT else [])
  pm = PubMaster(pub_socks)
  sm = SubMaster(["deviceState", "carState", "narrowRoadCameraState", "extrinsicsCalibration", "driverMonitoringState", "carControl", "lateralDelay"])

  publish_state = PublishState()
  params = Params()
-  chestnut_state = ChestnutState(pm, model.usbgpu) if USBGPU else None
+  chestnut_state = ChestnutState(pm, model.chestnut) if CHESTNUT else None

  # setup filter to track dropped frames
  frame_dropped_filter = FirstOrderFilter(0., 10., 1. / ModelConstants.MODEL_RUN_FREQ)
@@ -393,13 +397,15 @@ def main(demo=False):

    mt1 = time.perf_counter()
    try:
-      model_output = model.run(bufs, transforms, inputs)
+      send_chestnut = (chestnut_state is not None and
+                       run_count % round(ModelConstants.MODEL_RUN_FREQ / SERVICE_LIST['chestnutState'].frequency) == 0)
+      model_output = model.run(bufs, transforms, inputs, chestnut_state.send if send_chestnut else None)
    except Exception:
-      if not params.get_bool("UsbGpuActive"):
+      if not params.get_bool("ChestnutActive"):
        raise
      # fallback to small model
      cloudlog.exception("big model failed, fall back to small")
-      params.put_bool("UsbGpuActive", False)
+      params.put_bool("ChestnutActive", False)
      assert small_model is not None
      model = small_model
      if chestnut_state is not None:
@@ -419,7 +425,7 @@ def main(demo=False):
      fill_model_msg(modelv2_send, model_output, action,
                     publish_state, meta_main.frame_id, meta_extra.frame_id, frame_id,
                     frame_drop_ratio, meta_main.timestamp_eof, model_execution_time, extrinsics_calibration_seen)
-      modelv2_send.modelV2.big = model.usbgpu
+      modelv2_send.modelV2.big = model.chestnut

      desire_state = modelv2_send.modelV2.meta.desireState
      l_lane_change_prob = desire_state[log.Desire.laneChangeLeft]
@@ -441,10 +447,6 @@ def main(demo=False):
      pm.send('modelDataV2SP', mdv2sp_send)
    last_vipc_frame_id = meta_main.frame_id

-    if chestnut_state is not None and run_count % round(ModelConstants.MODEL_RUN_FREQ / SERVICE_LIST['chestnutState'].frequency) == 0:
-      chestnut_state.send()
-
-
 if __name__ == "__main__":
  try:
    import argparse
@@ -195,17 +195,18 @@ class SelfdriveD(CruiseHelper):
      self.events.add(EventName.joystickDebug)
      self.startup_event = None

-    loading = self.params.get_bool("UsbGpuLoading")
+    loading = self.params.get_bool("ChestnutLoading")
    if self.big_model_loading and not loading:
      self.big_model_ready_t = time.monotonic()
+      self.events_sp.add(custom.OnroadEventSP.EventName.bigModelReady)
    self.big_model_loading = loading
    if self.big_model_loading:
      self.events.add(EventName.bigModelLoading)

-    big_active = self.params.get("UsbGpuActive")
-    usbgpu_present = self.sm['deviceState'].chestnutPresent
+    big_active = self.params.get("ChestnutActive")
+    chestnut_present = self.sm['deviceState'].chestnutPresent
    model_unavailable = big_active is True and self.sm.seen['modelV2'] and not self.sm.alive['modelV2']
-    big_failed = big_active is False or model_unavailable or (self.big_model_active and not usbgpu_present)
+    big_failed = big_active is False or model_unavailable or (self.big_model_active and not chestnut_present)
    if big_failed and not self.big_model_failed:
      self.events.add(EventName.bigModelFailed)
    self.big_model_failed = big_failed
@@ -9,7 +9,7 @@ from openpilot.system.ui.widgets.layouts import HBoxLayout
 from openpilot.system.ui.widgets.icon_widget import IconWidget
 from openpilot.system.ui.widgets.label import UnifiedLabel, gui_label
 from openpilot.system.ui.lib.application import gui_app, FontWeight, MousePos
-from openpilot.selfdrive.ui.ui_state import ui_state
+from openpilot.selfdrive.ui.ui_state import ui_state, ChestnutState
 from openpilot.common.version import RELEASE_BRANCHES

 HEAD_BUTTON_FONT_SIZE = 40
@@ -139,8 +139,8 @@ class MiciHomeLayout(Widget):
    self._version_text = self._get_version_text()

    self._experimental_icon = IconWidget("icons_mici/experimental_mode.png", (48, 48))
-    self._egpu_icon = IconWidget("icons_mici/egpu_green.png", (50, 37))
-    self._egpu_icon_gray = IconWidget("icons_mici/egpu_gray.png", (50, 37))
+    self._chestnut_icon = IconWidget("icons_mici/chestnut_green.png", (68, 40))
+    self._chestnut_failed_icon = IconWidget("icons_mici/chestnut_orange.png", (68, 40))
    self._mic_icon = IconWidget("icons_mici/microphone.png", (32, 46))
    self._body_icon = IconWidget("icons_mici/body.png", (54, 37))

@@ -150,8 +150,8 @@ class MiciHomeLayout(Widget):
      IconWidget("icons_mici/settings.png", (48, 48), opacity=0.9),
      NetworkIcon(),
      self._experimental_icon,
-      self._egpu_icon,
-      self._egpu_icon_gray,
+      self._chestnut_icon,
+      self._chestnut_failed_icon,
      self._body_icon,
      self._mic_icon,
    ], spacing=18)
@@ -249,10 +249,10 @@ class MiciHomeLayout(Widget):
    # ***** Center-aligned bottom section icons *****
    self._experimental_icon.set_visible(ui_state.experimental_mode)
    if gui_app.sunnypilot_ui():
-      self._set_egpu_visibility()
+      self._set_chestnut_visibility()
    else:
-      self._egpu_icon.set_visible(ui_state.sm["deviceState"].chestnutPresent and ui_state.usbgpu_compiled)
-      self._egpu_icon_gray.set_visible(ui_state.sm["deviceState"].chestnutPresent and not ui_state.usbgpu_compiled)
+      self._chestnut_icon.set_visible(ui_state.chestnut_state in (ChestnutState.READY, ChestnutState.LOADING, ChestnutState.ACTIVE))
+      self._chestnut_failed_icon.set_visible(ui_state.chestnut_state in (ChestnutState.UNCOMPILED, ChestnutState.FAILED))
    self._mic_icon.set_visible(ui_state.recording_audio)
    self._body_icon.set_visible(bool(ui_state.is_body))

@@ -3,7 +3,7 @@ import pyray as rl
 from dataclasses import dataclass
 from openpilot.common.constants import CV
 from openpilot.selfdrive.ui.mici.onroad.torque_bar import TorqueBar
-from openpilot.selfdrive.ui.ui_state import ui_state, UIStatus
+from openpilot.selfdrive.ui.ui_state import ui_state, UIStatus, ChestnutState
 from openpilot.system.ui.lib.application import gui_app, FontWeight
 from openpilot.system.ui.lib.multilang import tr
 from openpilot.system.ui.lib.text_measure import measure_text_cached
@@ -107,8 +107,7 @@ class HudRenderer(Widget):
    self.speed: float = 0.0
    self.v_ego_cluster_seen: bool = False
    self._engaged: bool = False
-    self._small_model_engaged: bool = False
-    self._egpu_fade_time: float = 0
+    self._chestnut_fade_time: float = 0

    self._can_draw_top_icons = True
    self._show_wheel_critical = False
@@ -124,17 +123,15 @@ class HudRenderer(Widget):
    self._txt_wheel: rl.Texture = gui_app.texture('icons_mici/wheel.png', 50, 50)
    self._txt_wheel_critical: rl.Texture = gui_app.texture('icons_mici/wheel_critical.png', 50, 50)
    self._txt_exclamation_point: rl.Texture = gui_app.texture('icons_mici/exclamation_point.png', 9, 44)
-    self._txt_egpu: rl.Texture = gui_app.texture('icons_mici/egpu.png', 60, 44)
-    self._txt_egpu_green: rl.Texture = gui_app.texture('icons_mici/egpu_green.png', 60, 44)
-    self._txt_egpu_orange: rl.Texture = gui_app.texture('icons_mici/egpu_orange.png', 60, 44)
-    self._txt_egpu_crossed: rl.Texture = gui_app.texture('icons_mici/egpu_crossed.png', 60, 52)
-    self._egpu_icon: rl.Texture | None = None
-
+    self._txt_chestnut: rl.Texture = gui_app.texture('icons_mici/chestnut.png', 60, 44)
+    self._txt_chestnut_green: rl.Texture = gui_app.texture('icons_mici/chestnut_green.png', 60, 44)
+    self._txt_chestnut_orange: rl.Texture = gui_app.texture('icons_mici/chestnut_orange.png', 75, 44)
+    self._chestnut_icon: rl.Texture | None = None
    self._wheel_alpha_filter = FirstOrderFilter(0, 0.05, 1 / gui_app.target_fps)
    self._wheel_y_filter = FirstOrderFilter(0, 0.1, 1 / gui_app.target_fps)

    self._set_speed_alpha_filter = FirstOrderFilter(0.0, 0.1, 1 / gui_app.target_fps)
-    self._egpu_alpha_filter = FirstOrderFilter(0.0, 0.1, 1 / gui_app.target_fps)
+    self._chestnut_alpha_filter = FirstOrderFilter(0.0, 0.1, 1 / gui_app.target_fps)

  def set_wheel_critical_icon(self, critical: bool):
    """Set the wheel icon to critical or normal state."""
@@ -165,13 +162,10 @@ class HudRenderer(Widget):
      controls_state.deprecated.vCruise if v_cruise_cluster == 0.0 else v_cruise_cluster
    )
    engaged = sm['selfdriveState'].enabled
-    if (engaged and not self._engaged and not ui_state.usbgpu_loading and ui_state.usbgpu_active is not True and
-        ui_state.sm.recv_frame['modelV2'] > ui_state.started_frame):
-      self._small_model_engaged = True
-    if engaged != self._engaged:
-      self._egpu_fade_time = rl.get_time() if engaged else 0
    if (set_speed != self.set_speed and engaged) or (engaged and not self._engaged):
      self._set_speed_changed_time = rl.get_time()
+    if engaged != self._engaged:
+      self._chestnut_fade_time = rl.get_time() if engaged else 0
    self._engaged = engaged
    self.set_speed = set_speed
    self.is_cruise_set = 0 < self.set_speed < SET_SPEED_NA
@@ -191,8 +185,7 @@ class HudRenderer(Widget):
    if self.is_cruise_set:
      self._draw_set_speed(rect)

-    if ui_state.usbgpu and ui_state.usbgpu_compiled:
-      self._draw_model_source(rect)
+    self._draw_model_source(rect)

    self._draw_steering_wheel(rect)

@@ -200,30 +193,24 @@ class HudRenderer(Widget):
    if ui_state.sm.recv_frame['selfdriveState'] < ui_state.started_frame:
      return

-    big_failed = (ui_state.usbgpu_active is False or not ui_state.sm['deviceState'].chestnutPresent or
-                  (ui_state.usbgpu_active is True and ui_state.sm.recv_frame['modelV2'] > ui_state.started_frame and
-                   not ui_state.sm.alive['modelV2']) or
-                  (ui_state.usbgpu_active is None and ui_state.sm.recv_frame['modelV2'] > ui_state.started_frame))
-    self._small_model_engaged &= big_failed
-    loading = ui_state.usbgpu_loading or (ui_state.usbgpu_active is None and not big_failed)
+    loading = ui_state.chestnut_state == ChestnutState.LOADING
    if loading:
-      pulse = 0.5 - 0.5 * math.cos(rl.get_time() * 6.0)
-      icon = self._txt_egpu
-      opacity = 0.35 + 0.65 * pulse
-    elif self._small_model_engaged:
-      icon = self._txt_egpu_crossed
-      opacity = 0.65
-    elif big_failed:
-      icon = self._txt_egpu_orange
+      icon = self._txt_chestnut
+      opacity = 0.35 + 0.65 * (0.5 - 0.5 * math.cos(rl.get_time() * 6.0))
+    elif ui_state.chestnut_state in (ChestnutState.UNCOMPILED, ChestnutState.FAILED):
+      icon = self._txt_chestnut_orange
+      opacity = 1.0
+    elif ui_state.chestnut_state == ChestnutState.ACTIVE:
+      icon = self._txt_chestnut_green
      opacity = 1.0
    else:
-      icon = self._txt_egpu_green
-      opacity = 1.0
+      return

-    if icon is not self._egpu_icon:
-      self._egpu_fade_time = rl.get_time()
-      self._egpu_icon = icon
-    alpha = self._egpu_alpha_filter.update(loading or 0 < rl.get_time() - self._egpu_fade_time < SET_SPEED_PERSISTENCE)
+    if icon is not self._chestnut_icon:
+      self._chestnut_fade_time = rl.get_time()
+      self._chestnut_icon = icon
+    visible = loading or rl.get_time() - self._chestnut_fade_time < SET_SPEED_PERSISTENCE
+    alpha = self._chestnut_alpha_filter.update(visible)
    if alpha < 1e-2:
      return

@@ -62,14 +62,14 @@ class ModelsLayout(Widget):
    self.big_model_item = ListItemSP(
      title=tr("Big Model"),
      action_item=ScrollingButtonAction(tr("SELECT")),
-      callback=lambda: self._open_source_dialog("usbgpu")
+      callback=lambda: self._open_source_dialog("chestnut")
    )

    self.download_item = download_status_item(lambda: tr("Download") if self._downloading else tr("Model Status"))

    self.refresh_item = button_item(tr("Refresh Model List"), tr("REFRESH"), "",
                                    lambda: (ui_state.params.put("ModelManager_LastSyncTime", 0),
-                                             ui_state.params.put("ModelManager_LastSyncTime_USBGPU", 0),
+                                             ui_state.params.put("ModelManager_LastSyncTime_Chestnut", 0),
                                             gui_app.push_widget(alert_dialog(tr("Fetching Latest Models")))))

    self.clear_cache_item = ListItemSP(
@@ -177,14 +177,14 @@ class ModelsLayout(Widget):
    big_state = big_model_state()
    carry_source, carry_internal, _ = carrying_model()
    segments = []
-    for source, label in (("qcom", tr("small")), ("usbgpu", tr("big"))):
+    for source, label in (("qcom", tr("small")), ("chestnut", tr("big"))):
      if segments:
        segments.append(("|", rl.GRAY, None, None))
      bundle = get_selected_bundle(ui_state.params, source)
      name = bundle.internalName if bundle else default_model_name(source)
      color = ON_COLOR if (source == carry_source and name == carry_internal) else rl.LIGHTGRAY
      name = "● " + name
-      if source == "usbgpu":
+      if source == "chestnut":
        if big_state == 'failed':
          color = rl.RED
        elif big_state == 'loading':
@@ -208,10 +208,10 @@ class ModelsLayout(Widget):
    """The failover story for the Model Status row. One-way big -> small, and the
    fallback is runner-matched: a Default big can only fall back to the Default
    small (stock modeld), a custom big has no automatic fallback yet."""
-    if not ui_state.usbgpu:
+    if not ui_state.chestnut_present:
      return ""
-    big_bundle = get_selected_bundle(ui_state.params, "usbgpu")
-    big_name = big_bundle.internalName if big_bundle else default_model_name("usbgpu")
+    big_bundle = get_selected_bundle(ui_state.params, "chestnut")
+    big_name = big_bundle.internalName if big_bundle else default_model_name("chestnut")
    big_is_default = big_bundle is None
    fallback_name = default_model_name("qcom")
    state = big_model_state()
@@ -225,7 +225,7 @@ class ModelsLayout(Widget):
      return tr("Getting the big model ready.")
    if big_is_default:
      return tr("{} will drive. If it fails during a drive, {} takes over until the next drive.").format(big_name, fallback_name)
-    return tr("{} will drive when the eGPU is ready.").format(big_name)
+    return tr("{} will drive when the chestnut is ready.").format(big_name)

  @staticmethod
  def _download_row_state(progresses, name: str) -> dict:
@@ -261,7 +261,7 @@ class ModelsLayout(Widget):
      ui_state.params.put("ModelManager_DownloadRef", selected_bundle.ref)

  def _resolve_selected_bundle(self, ref):
-    source_bundles = {source: bundles_for_source(source) for source in ("qcom", "usbgpu")}
+    source_bundles = {source: bundles_for_source(source) for source in ("qcom", "chestnut")}
    resolved = resolve_bundle_by_ref(ref, source_bundles)
    return resolved[0] if resolved else None

@@ -329,7 +329,7 @@ class ModelsLayout(Widget):
    self._handle_bundle_download_progress()

    carry_source, _, carry_display = carrying_model()
-    for item, item_source in ((self.small_model_item, "qcom"), (self.big_model_item, "usbgpu")):
+    for item, item_source in ((self.small_model_item, "qcom"), (self.big_model_item, "chestnut")):
      bundle = get_selected_bundle(ui_state.params, item_source)
      name = bundle.displayName if bundle else default_model_name(item_source)
      color = ON_COLOR if (item_source == carry_source and name == carry_display) else style.ITEM_TEXT_VALUE_COLOR
@@ -9,7 +9,7 @@ import math
 import pyray as rl
 import time
 from dataclasses import dataclass
-from openpilot.selfdrive.ui.ui_state import ui_state
+from openpilot.selfdrive.ui.ui_state import ui_state, ChestnutState
 from openpilot.sunnypilot.sunnylink.api import UNREGISTERED_SUNNYLINK_DONGLE_ID
 from openpilot.system.ui.lib.application import gui_app
 from openpilot.system.ui.lib.multilang import tr_noop
@@ -21,8 +21,8 @@ METRIC_MARGIN = 30
 METRIC_START_Y = 300
 HOME_BTN = rl.Rectangle(60, 860, 180, 180)

-EGPU_ICON_WIDTH = 180
-EGPU_ICON_HEIGHT = 133
+CHESTNUT_ICON_WIDTH = 180
+CHESTNUT_ICON_HEIGHT = 133


 # Color scheme
@@ -59,10 +59,9 @@ class MetricData:
 class SidebarSP:
  def __init__(self):
    self._sunnylink_status = MetricData(tr_noop("SUNNYLINK"), tr_noop("OFFLINE"), Colors.WARNING)
-    self._egpu_green_img = gui_app.texture("icons_mici/egpu_green.png", EGPU_ICON_WIDTH, EGPU_ICON_HEIGHT)
-    self._egpu_default_img = gui_app.texture("icons_mici/egpu.png", EGPU_ICON_WIDTH, EGPU_ICON_HEIGHT)
-    self._egpu_orange_img = gui_app.texture("icons_mici/egpu_orange.png", EGPU_ICON_WIDTH, EGPU_ICON_HEIGHT)
-    self._egpu_gray_img = gui_app.texture("icons_mici/egpu_gray.png", EGPU_ICON_WIDTH, EGPU_ICON_HEIGHT)
+    self._chestnut_green_img = gui_app.texture("icons_mici/chestnut_green.png", CHESTNUT_ICON_WIDTH, CHESTNUT_ICON_HEIGHT)
+    self._chestnut_default_img = gui_app.texture("icons_mici/chestnut.png", CHESTNUT_ICON_WIDTH, CHESTNUT_ICON_HEIGHT)
+    self._chestnut_orange_img = gui_app.texture("icons_mici/chestnut_orange.png", CHESTNUT_ICON_WIDTH, CHESTNUT_ICON_HEIGHT)

  def _update_sunnylink_status(self):
    if not ui_state.params.get_bool("SunnylinkEnabled"):
@@ -90,22 +89,17 @@ class SidebarSP:

  def _get_home_icon(self, default_img: rl.Texture) -> tuple[rl.Texture, rl.Vector2, float]:
    default_pos = rl.Vector2(HOME_BTN.x, HOME_BTN.y)
-    if not ui_state.sm["deviceState"].chestnutPresent:
+    state = ui_state.chestnut_state
+    if state == ChestnutState.DISCONNECTED:
      return default_img, default_pos, 1.0

-    big_model_selected = ui_state.usbgpu_compiled or ui_state.model_runner_tinygrad
-    big_model_failed = ui_state.started and ui_state.big_model_failed
-    loading = ui_state.usbgpu_loading or (big_model_selected and ui_state.started and ui_state.usbgpu_active is None)
-
-    if loading:
-      icon = self._egpu_default_img
+    if state == ChestnutState.LOADING:
+      icon = self._chestnut_default_img
      opacity = 0.35 + 0.65 * (0.5 - 0.5 * math.cos(rl.get_time() * 6.0))
-    elif big_model_selected and big_model_failed:
-      icon, opacity = self._egpu_orange_img, 1.0
-    elif big_model_selected:
-      icon, opacity = self._egpu_green_img, 1.0
+    elif state in (ChestnutState.UNCOMPILED, ChestnutState.FAILED):
+      icon, opacity = self._chestnut_orange_img, 1.0
    else:
-      icon, opacity = self._egpu_gray_img, 1.0
+      icon, opacity = self._chestnut_green_img, 1.0

    x = HOME_BTN.x + (HOME_BTN.width - icon.width) / 2
    y = HOME_BTN.y + (HOME_BTN.height - icon.height) / 2
@@ -9,7 +9,7 @@ import math
 import pyray as rl

 from openpilot.selfdrive.ui.mici.layouts.home import MiciHomeLayout
-from openpilot.selfdrive.ui.ui_state import ui_state
+from openpilot.selfdrive.ui.ui_state import ui_state, ChestnutState
 from openpilot.system.ui.lib.application import FontWeight
 from openpilot.system.ui.widgets.icon_widget import IconWidget
 from openpilot.system.ui.widgets.label import UnifiedLabel
@@ -19,35 +19,16 @@ class MiciHomeLayoutSP(MiciHomeLayout):
  def __init__(self):
    super().__init__()
    self._openpilot_label = UnifiedLabel("sunnypilot", font_size=88, font_weight=FontWeight.AUDIOWIDE, max_width=480, wrap_text=False)
-    self._egpu_icon_default = IconWidget("icons_mici/egpu.png", (50, 37))
-    self._egpu_icon_default.set_visible(False)
-    self._egpu_icon_orange = IconWidget("icons_mici/egpu_orange.png", (50, 37))
-    self._egpu_icon_orange.set_visible(False)
-    gray_idx = self._status_bar_layout.widgets.index(self._egpu_icon_gray)
-    self._status_bar_layout.widgets.insert(gray_idx + 1, self._egpu_icon_default)
-    self._status_bar_layout.widgets.insert(gray_idx + 2, self._egpu_icon_orange)
+    self._chestnut_loading_icon = IconWidget("icons_mici/chestnut.png", (68, 40))
+    self._chestnut_loading_icon.set_visible(False)
+    failed_idx = self._status_bar_layout.widgets.index(self._chestnut_failed_icon)
+    self._status_bar_layout.widgets.insert(failed_idx + 1, self._chestnut_loading_icon)

-  def _set_egpu_visibility(self):
-    chestnut = ui_state.sm["deviceState"].chestnutPresent
-    if not chestnut:
-      self._egpu_icon.set_visible(False)
-      self._egpu_icon_default.set_visible(False)
-      self._egpu_icon_orange.set_visible(False)
-      self._egpu_icon_gray.set_visible(False)
-      return
-
-    big_model_selected = ui_state.usbgpu_compiled or ui_state.model_runner_tinygrad
-    big_model_failed = ui_state.started and ui_state.big_model_failed
-    loading = ui_state.usbgpu_loading or (big_model_selected and ui_state.started and ui_state.usbgpu_active is None)
-
-    if loading:
-      self._egpu_icon_default._opacity = 0.35 + 0.65 * (0.5 - 0.5 * math.cos(rl.get_time() * 6.0))
-      self._egpu_icon_default.set_visible(True)
-      self._egpu_icon.set_visible(False)
-      self._egpu_icon_orange.set_visible(False)
-      self._egpu_icon_gray.set_visible(False)
-    else:
-      self._egpu_icon_default.set_visible(False)
-      self._egpu_icon.set_visible(big_model_selected and not big_model_failed)
-      self._egpu_icon_orange.set_visible(big_model_selected and big_model_failed)
-      self._egpu_icon_gray.set_visible(not big_model_selected)
+  def _set_chestnut_visibility(self):
+    # stock has no loading tier: it shows green from the moment a big model is available. keep the
+    # pulse so the status bar and the onroad HUD agree on what loading looks like.
+    loading = ui_state.chestnut_state == ChestnutState.LOADING
+    self._chestnut_loading_icon._opacity = 0.35 + 0.65 * (0.5 - 0.5 * math.cos(rl.get_time() * 6.0))
+    self._chestnut_loading_icon.set_visible(loading)
+    self._chestnut_icon.set_visible(not loading and ui_state.chestnut_state in (ChestnutState.READY, ChestnutState.ACTIVE))
+    self._chestnut_failed_icon.set_visible(ui_state.chestnut_state in (ChestnutState.UNCOMPILED, ChestnutState.FAILED))
@@ -27,14 +27,14 @@ def _model_info() -> tuple[str, str, str]:
  state = big_model_state()
  _, _, carry_display = carrying_model()
  if carry_display is None:
-    big = get_selected_bundle(ui_state.params, "usbgpu")
-    carry_display = big.displayName if big else default_model_name("usbgpu")
+    big = get_selected_bundle(ui_state.params, "chestnut")
+    carry_display = big.displayName if big else default_model_name("chestnut")
  active_text = (carry_display or active_name).lower()
  if state == 'failed':
    return active_text, tr("big model"), tr("unavailable")
  if state == 'loading':
    return active_text, tr("big model"), tr("getting ready")
-  header = tr("small model") if source == "usbgpu" else tr("big model")
+  header = tr("small model") if source == "chestnut" else tr("big model")
  return active_text, header, other_name.lower()


@@ -113,7 +113,7 @@ class ModelsLayoutMici(NavScroller):

    hardware_btns = []
    active = active_source()
-    for source, label in (("qcom", tr("small models")), ("usbgpu", tr("big models"))):
+    for source, label in (("qcom", tr("small models")), ("chestnut", tr("big models"))):
      bundle = get_selected_bundle(ui_state.params, source)
      value = (bundle.internalName if bundle else default_model_name(source)).lower()
      if source == active:
@@ -7,7 +7,6 @@ See the LICENSE.md file in the root directory for more details.
 import pyray as rl

 from openpilot.selfdrive.ui.mici.onroad.hud_renderer import HudRenderer
-from openpilot.selfdrive.ui.ui_state import ui_state
 from openpilot.selfdrive.ui.sunnypilot.onroad.blind_spot_indicators import BlindSpotIndicators


@@ -22,8 +21,6 @@ class HudRendererSP(HudRenderer):

  def _render(self, rect: rl.Rectangle) -> None:
    super()._render(rect)
-    if ui_state.usbgpu and not ui_state.usbgpu_compiled and ui_state.model_runner_tinygrad:
-      self._draw_model_source(rect)
    self.blind_spot_indicators.render(rect)

  def _has_blind_spot_detected(self) -> bool:
@@ -4,15 +4,15 @@ Copyright (c) 2021-, Haibin Wen, sunnypilot, and a number of other contributors.
 This file is part of sunnypilot and is licensed under the MIT License.
 See the LICENSE.md file in the root directory for more details.
 """
-from openpilot.selfdrive.ui.ui_state import ui_state
+from openpilot.selfdrive.ui.ui_state import ui_state, ChestnutState
 from openpilot.sunnypilot.models.fetcher import get_cached_bundles
 from openpilot.sunnypilot.models.helpers import get_active_source, get_selected_bundle, resolve_bundle_by_ref
 from openpilot.sunnypilot.models.model_name import DEFAULT_BIG_MODEL, DEFAULT_MODEL


 def active_source() -> str:
-  return get_active_source(usbgpu=ui_state.usbgpu,
-                           usbgpu_active=ui_state.usbgpu_active, usbgpu_loading=ui_state.usbgpu_loading,
+  return get_active_source(chestnut=ui_state.chestnut_present,
+                           chestnut_active=ui_state.chestnut_active, chestnut_loading=ui_state.chestnut_loading,
                           offroad=ui_state.is_offroad())


@@ -23,7 +23,7 @@ def bundles_for_source(source: str):


 def default_model(source: str) -> str:
-  return DEFAULT_BIG_MODEL if source == 'usbgpu' else DEFAULT_MODEL
+  return DEFAULT_BIG_MODEL if source == 'chestnut' else DEFAULT_MODEL


 def default_model_name(source: str) -> str:
@@ -31,13 +31,10 @@ def default_model_name(source: str) -> str:


 def big_model_state() -> str | None:
-  """'failed' | 'loading' | None, mirroring the sidebar's detection (#1969)."""
-  if ui_state.started and ui_state.usbgpu and ui_state.big_model_failed:
-    return 'failed'
-  big_selected = ui_state.usbgpu_compiled or ui_state.model_runner_tinygrad
-  if ui_state.usbgpu_loading or (big_selected and ui_state.started and ui_state.usbgpu_active is None):
-    return 'loading'
-  return None
+  """'failed' | 'loading' | None, from the same state the icons render."""
+  return {ChestnutState.UNCOMPILED: 'failed',
+          ChestnutState.FAILED: 'failed',
+          ChestnutState.LOADING: 'loading'}.get(ui_state.chestnut_state)


 def carrying_model() -> tuple[str | None, str | None, str | None]:
@@ -45,14 +42,14 @@ def carrying_model() -> tuple[str | None, str | None, str | None]:
  when a Default big cannot carry, stock modeld runs the Default small, never the
  small slot's pick; a custom big has no automatic fallback yet -> (None, None, None)."""
  source = active_source()
-  if source == "usbgpu":
-    bundle = get_selected_bundle(ui_state.params, "usbgpu")
+  if source == "chestnut":
+    bundle = get_selected_bundle(ui_state.params, "chestnut")
    if bundle:
-      return "usbgpu", bundle.internalName, bundle.displayName
-    name = default_model_name("usbgpu")
-    return "usbgpu", name, name
-  if ui_state.usbgpu:
-    if get_selected_bundle(ui_state.params, "usbgpu") is None:
+      return "chestnut", bundle.internalName, bundle.displayName
+    name = default_model_name("chestnut")
+    return "chestnut", name, name
+  if ui_state.chestnut_present:
+    if get_selected_bundle(ui_state.params, "chestnut") is None:
      name = default_model_name("qcom")
      return "qcom", name, name
    return None, None, None
@@ -66,7 +63,7 @@ def carrying_model() -> tuple[str | None, str | None, str | None]:
 def queued_name(current_ref) -> str | None:
  ref = ui_state.params.get("ModelManager_DownloadRef")
  if ref and ref != current_ref:
-    source_bundles = {source: bundles_for_source(source) for source in ("qcom", "usbgpu")}
+    source_bundles = {source: bundles_for_source(source) for source in ("qcom", "chestnut")}
    if resolved := resolve_bundle_by_ref(ref, source_bundles):
      return resolved[0].internalName
  return None
@@ -79,7 +76,7 @@ def model_info() -> tuple[str, str, str]:
  manager republishes a tick after a chestnut change, so the stale bundle
  would flash the wrong model."""
  source = active_source()
-  other = "qcom" if source == "usbgpu" else "usbgpu"
+  other = "qcom" if source == "chestnut" else "chestnut"
  active_bundle = get_selected_bundle(ui_state.params, source)
  other_bundle = get_selected_bundle(ui_state.params, other)

@@ -152,10 +152,13 @@ class UIStateSP:
      self.has_icbm = self.CP_SP.intelligentCruiseButtonManagementAvailable and self.params.get_bool("IntelligentCruiseButtonManagement")

    self._enforce_constraints()
-    source = get_active_source(usbgpu=self.usbgpu, usbgpu_active=self.usbgpu_active,
-                               usbgpu_loading=self.usbgpu_loading, offroad=self.is_offroad())
+    source = get_active_source(chestnut=self.chestnut_present, chestnut_active=self.chestnut_active,
+                               chestnut_loading=self.chestnut_loading, offroad=self.is_offroad())
    self.active_bundle = self.params.get(ACTIVE_BUNDLE_KEYS[source])
    self.model_runner_tinygrad = self.active_bundle is not None and self.active_bundle.get("runner") == "tinygrad"
+    # stock only counts the default big model's compiled pkl. a downloaded big bundle runs on the
+    # chestnut just the same, so ChestnutState has to see it as available too.
+    self.chestnut_compiled = self.chestnut_compiled or self.model_runner_tinygrad
    self.blindspot = self.params.get_bool("BlindSpot")
    self.chevron_metrics = self.params.get("ChevronInfo")
    self.custom_interactive_timeout = self.params.get("InteractivityTimeout", return_default=True)
@@ -12,7 +12,7 @@ from openpilot.common.swaglog import cloudlog
 from openpilot.selfdrive.ui.lib.prime_state import PrimeState
 from openpilot.system.ui.lib.application import gui_app
 from openpilot.common.hardware import HARDWARE, PC
-from openpilot.selfdrive.modeld.helpers import usbgpu_compiled
+from openpilot.selfdrive.modeld.helpers import chestnut_compiled

 from openpilot.selfdrive.ui.sunnypilot.ui_state import UIStateSP, DeviceSP

@@ -28,6 +28,15 @@ class UIStatus(Enum):
  LONG_ONLY = "long_only"


+class ChestnutState(Enum):
+  DISCONNECTED = "disconnected"
+  UNCOMPILED = "uncompiled"
+  READY = "ready"
+  LOADING = "loading"
+  ACTIVE = "active"
+  FAILED = "failed"
+
+
 class UIState(UIStateSP):
  _instance: 'UIState | None' = None

@@ -82,10 +91,11 @@ class UIState(UIStateSP):
    self.always_on_dm: bool = self.params.get_bool("AlwaysOnDM")
    self.experimental_mode: bool = self.params.get_bool("ExperimentalMode")
    self.experimental_mode_confirmed: bool = self.params.get_bool("ExperimentalModeConfirmed")
-    self.usbgpu: bool = False
-    self.usbgpu_compiled: bool = usbgpu_compiled()
-    self.usbgpu_active: bool | None = self.params.get("UsbGpuActive")
-    self.usbgpu_loading: bool = self.params.get_bool("UsbGpuLoading")
+    self.chestnut_present: bool = False
+    self.chestnut_compiled: bool = chestnut_compiled()
+    self.chestnut_active: bool | None = None
+    self.chestnut_loading: bool = False
+    self.chestnut_state = ChestnutState.DISCONNECTED
    self.started: bool = False
    self.ignition: bool = False
    self.recording_audio: bool = False
@@ -112,15 +122,6 @@ class UIState(UIStateSP):
  def add_on_body_changed_callbacks(self, callback: Callable[[], None]):
    self._on_body_changed_callbacks.append(callback)

-  @property
-  def big_model_failed(self) -> bool:
-    # Mirrors the onroad HUD's four-condition check so sidebar and home icons reflect the same failure states
-    return (self.usbgpu_active is False or
-            not self.sm['deviceState'].chestnutPresent or
-            (self.usbgpu_active is True and self.sm.recv_frame['modelV2'] > self.started_frame and
-             not self.sm.alive['modelV2']) or
-            (self.usbgpu_active is None and self.sm.recv_frame['modelV2'] > self.started_frame))
-
  @property
  def engaged(self) -> bool:
    return self.started and (self.sm["selfdriveState"].enabled or self.sm["selfdriveStateSP"].mads.enabled)
@@ -140,6 +141,7 @@ class UIState(UIStateSP):
    self.sm.update(0)
    self._update_state()
    self._update_status()
+    self._update_chestnut_state()
    device.update()
    UIStateSP.update(self)

@@ -203,12 +205,35 @@ class UIState(UIStateSP):
        self.status = UIStatus.DISENGAGED
        self.started_frame = self.sm.frame
        self.started_time = time.monotonic()
+        self.chestnut_present = self.sm["deviceState"].chestnutPresent

      for callback in self._offroad_transition_callbacks:
        callback()

      self._started_prev = self.started

+  def _update_chestnut_state(self) -> None:
+    detected = self.sm["deviceState"].chestnutPresent
+    if not self.started:
+      self.chestnut_present = detected
+      self.chestnut_state = (ChestnutState.READY if detected and self.chestnut_compiled else
+                             ChestnutState.UNCOMPILED if detected else ChestnutState.DISCONNECTED)
+      return
+
+    model_seen = self.sm.recv_frame["modelV2"] > self.started_frame
+    if not self.chestnut_present:
+      self.chestnut_state = ChestnutState.DISCONNECTED
+    elif not self.chestnut_compiled:
+      self.chestnut_state = ChestnutState.UNCOMPILED
+    elif self.chestnut_state == ChestnutState.FAILED or not detected or (model_seen and (not self.sm.alive["modelV2"] or not self.sm["modelV2"].big)):
+      self.chestnut_state = ChestnutState.FAILED
+    elif self.chestnut_loading or not model_seen:
+      self.chestnut_state = ChestnutState.LOADING
+    elif self.chestnut_active is False:
+      self.chestnut_state = ChestnutState.FAILED
+    else:
+      self.chestnut_state = ChestnutState.ACTIVE
+
  def update_params(self) -> None:
    # For slower operations
    # Update longitudinal control state
@@ -225,12 +250,10 @@ class UIState(UIStateSP):
    self.always_on_dm = self.params.get_bool("AlwaysOnDM")
    self.experimental_mode = self.params.get_bool("ExperimentalMode")
    self.experimental_mode_confirmed = self.params.get_bool("ExperimentalModeConfirmed")
-    # keep usbgpu UI active until offroad transition when gpu disappears
-    self.usbgpu = self.sm["deviceState"].chestnutPresent or (self.usbgpu and self.started)
-    if not self.usbgpu_compiled:
-      self.usbgpu_compiled = usbgpu_compiled()
-    self.usbgpu_active = self.params.get("UsbGpuActive")
-    self.usbgpu_loading = self.params.get_bool("UsbGpuLoading")
+    if not self.chestnut_compiled:
+      self.chestnut_compiled = chestnut_compiled()
+    self.chestnut_active = self.params.get("ChestnutActive")
+    self.chestnut_loading = self.params.get_bool("ChestnutLoading")

    UIStateSP.update_params(self)

@@ -298,7 +298,7 @@ def _load_policy_runners(args: argparse.Namespace) -> tuple[list, list]:


 if __name__ == "__main__":
-  if 'USB' in os.getenv('DEV', '') or os.getenv('USBGPU'):
+  if 'USB' in os.getenv('DEV', '') or os.getenv('CHESTNUT'):
    from openpilot.system.hardware.chestnut.flash import link_up
    for _ in range(10):
      if link_up():
@@ -8,22 +8,22 @@ See the LICENSE.md file in the root directory for more details.

 import os
 os.environ['GMMU'] = '0'
-from openpilot.common.hardware import COMMA_HARDWARE
-from openpilot.selfdrive.modeld.helpers import usbgpu_present, load_oob
-import time
 import numpy as np
+import threading
+import time
+from setproctitle import setproctitle
+from tinygrad.tensor import Tensor
+
 import openpilot.cereal.messaging as messaging
+from openpilot.common.hardware import COMMA_HARDWARE
+from openpilot.selfdrive.modeld.helpers import chestnut_present, load_oob
 from openpilot.cereal import log
 from opendbc.car.structs import car
 from openpilot.cereal.services import SERVICE_LIST
-from setproctitle import setproctitle
 from openpilot.cereal.messaging import PubMaster, SubMaster
 from openpilot.cereal.visionipc import VisionStreamType
 from msgq.visionipc import VisionIpcClient, VisionBuf
 from opendbc.car.car_helpers import get_demo_car_params
-
-from tinygrad.tensor import Tensor
-
 from openpilot.common.file_chunker import open_file_chunked
 from openpilot.common.swaglog import cloudlog
 from openpilot.common.params import Params
@@ -42,13 +42,13 @@ from openpilot.sunnypilot.modeld_v2.constants import Plan
 from openpilot.sunnypilot.modeld_v2.meta_helper import load_meta_constants
 from openpilot.sunnypilot.modeld_v2.camera_offset_helper import CameraOffsetHelper
 from openpilot.sunnypilot.modeld_v2.compile_modeld import derive_frame_skip, make_split_input_queues, make_supercombo_input_queues, WARP_INPUTS, POLICY_INPUTS
-
 from openpilot.sunnypilot.livedelay.helpers import get_lat_delay
 from openpilot.sunnypilot.modeld_v2.modeld_base import ModelStateBase
 from openpilot.sunnypilot.models.helpers import get_active_bundle
 from openpilot.sunnypilot.selfdrive.controls.lib.relc import RoadEdgeLaneChangeController

 PROCESS_NAME = "openpilot.selfdrive.modeld.modeld_tinygrad"
+BIG_MODEL_TIMEOUT = 60


 def _pkl_exists(path):
@@ -68,6 +68,7 @@ def _find_driving_pkl(bundle):
  pkl_path = os.path.join(model_root, pkl_name)
  if _pkl_exists(pkl_path):
    return pkl_path
+  return None


 class FrameMeta:
@@ -84,14 +85,14 @@ class ModelState(ModelStateBase):
  inputs: dict[str, np.ndarray]
  prev_desire: np.ndarray

-  def __init__(self, cam_w: int, cam_h: int, usbgpu: bool = False):
+  def __init__(self, cam_w: int, cam_h: int, chestnut: bool = False):
    ModelStateBase.__init__(self)

    env_pkl = os.environ.get('COMBINED_MODEL_PKL')
    if env_pkl and os.path.exists(env_pkl):
      model_bundle = None
    else:
-      model_bundle = get_active_bundle(usbgpu=usbgpu)
+      model_bundle = get_active_bundle(chestnut=chestnut)
    self.generation = model_bundle.generation if model_bundle is not None else None
    overrides = {override.key: override.value for override in model_bundle.overrides} if model_bundle else {}

@@ -99,10 +100,10 @@ class ModelState(ModelStateBase):
    self.LONG_SMOOTH_SECONDS = float(overrides.get('long', ".0"))
    self.MIN_LAT_CONTROL_SPEED = 0.3
    self.PLANPLUS_CONTROL: float = 1.0
-    self.usbgpu = usbgpu
+    self.chestnut = chestnut

    pkl_path = _find_driving_pkl(model_bundle)
-    assert pkl_path is not None, "No driving pkl found — all models must be compiled with compile_modeld.py"
+    assert pkl_path is not None, f"No driving pkl found for {'chestnut' if chestnut else 'small model'} — all models must be compiled with compile_modeld.py"
    self._init_combined(pkl_path, cam_w, cam_h, model_bundle)

  def _init_combined(self, pkl_path, cam_w, cam_h, bundle):
@@ -110,7 +111,7 @@ class ModelState(ModelStateBase):
    jits = load_oob(open_file_chunked(pkl_path))

    self.WARP_DEV = 'QCOM' if COMMA_HARDWARE else 'CPU'
-    self.DEV = 'AMD' if self.usbgpu else self.WARP_DEV
+    self.DEV = 'AMD' if self.chestnut else self.WARP_DEV
    self.QUEUE_DEV = self.DEV
    metadata = jits['metadata']

@@ -185,9 +186,6 @@ class ModelState(ModelStateBase):
    else:
      self.warp(**{k: self.input_queues[k] for k in WARP_INPUTS}, frame=frame_tensor, big_frame=big_frame_tensor)

-    if self.usbgpu:
-      self.warmup()
-
  def warmup(self) -> None:
    dummy_frames = {k: np.zeros(self.frame_buf_params[k][3], dtype=np.uint8) for k in self._vision_input_names}
    transforms = {k: np.eye(3, dtype=np.float32) for k in [self._road_key, self._wide_key] if k}
@@ -287,9 +285,8 @@ class ModelState(ModelStateBase):
      buf[0, :-1] = buf[0, 1:]
      buf[0, -1, :] = outputs['desired_curvature'][0, :] if not self.mlsim else 0

-    if self.usbgpu and not np.all(np.isfinite(outputs.get('plan', np.array([0.])))):
-      cloudlog.error("model output not finite, dropping frame")
-      return None
+    if self.chestnut and not np.all(np.isfinite(outputs.get('plan', np.array([0.])))):
+      raise RuntimeError("model output not finite")

    return outputs

@@ -327,13 +324,13 @@ def main(demo=False):
  setproctitle(PROCESS_NAME)
  config_realtime_process(7, 54)

-  USBGPU = usbgpu_present()
-  if USBGPU:
+  CHESTNUT = chestnut_present()
+  if CHESTNUT:
    os.environ['HCQDEV_WAIT_TIMEOUT_MS'] = '3000'

  params = Params()
-  params.put_bool("UsbGpuLoading", USBGPU)
-  params.remove("UsbGpuActive")
+  params.put_bool("ChestnutLoading", CHESTNUT)
+  params.remove("ChestnutActive")

  # visionipc clients
  while True:
@@ -362,31 +359,36 @@ def main(demo=False):
  st = time.monotonic()

  model = None
-  if USBGPU:
-    import threading
-    def load():
-      nonlocal model
-      model = ModelState(cam_w=vipc_client_main.width, cam_h=vipc_client_main.height, usbgpu=True)
-    t = threading.Thread(target=load, daemon=True)
-    t.start()
-    t.join(60)
-    if model is None:
-      params.put_bool("UsbGpuActive", False)
-      raise RuntimeError("eGPU model load failed or timed out (60s)")
-    params.put_bool("UsbGpuActive", True)
-  else:
-    model = ModelState(cam_w=vipc_client_main.width, cam_h=vipc_client_main.height, usbgpu=False)
+  if CHESTNUT:
+    big_model = None
+    def load_big():
+      nonlocal big_model
+      try:
+        m = ModelState(cam_w=vipc_client_main.width, cam_h=vipc_client_main.height, chestnut=True)
+        m.warmup()
+        big_model = m
+      except Exception:
+        cloudlog.exception("chestnut load failed")
+    loader = threading.Thread(target=load_big, daemon=True)
+    loader.start()
+    loader.join(BIG_MODEL_TIMEOUT)
+    model = big_model
+    params.put_bool("ChestnutActive", model is not None)

-  params.put_bool("UsbGpuLoading", False)
+  small_model = ModelState(cam_w=vipc_client_main.width, cam_h=vipc_client_main.height, chestnut=False) if model is None or CHESTNUT else None
+  if model is None:
+    model = small_model
+  params.put_bool("ChestnutLoading", False)
+  assert model is not None
  cloudlog.warning(f"models loaded in {time.monotonic() - st:.1f}s, modeld starting")

  # messaging
-  pub_socks = ["modelV2", "drivingModelData", "cameraOdometry", "modelDataV2SP"] + (["chestnutState"] if USBGPU else [])
+  pub_socks = ["modelV2", "drivingModelData", "cameraOdometry", "modelDataV2SP"] + (["chestnutState"] if CHESTNUT else [])
  pm = PubMaster(pub_socks)
  sm = SubMaster(["deviceState", "carState", "narrowRoadCameraState", "extrinsicsCalibration", "driverMonitoringState", "carControl", "lateralDelay"])

  publish_state = PublishState()
-  chestnut_state = ChestnutState(pm, USBGPU) if USBGPU else None
+  chestnut_state = ChestnutState(pm, model.chestnut) if CHESTNUT else None

  # setup filter to track dropped frames
  frame_dropped_filter = FirstOrderFilter(0., 10., 1. / model.constants.MODEL_FREQ)
@@ -509,7 +511,19 @@ def main(demo=False):
      inputs['action_t'] = np.array([lat_action_t, long_action_t], dtype=np.float32)

    mt1 = time.perf_counter()
-    model_output = model.run(bufs, transforms, inputs, prepare_only)
+    try:
+      model_output = model.run(bufs, transforms, inputs, prepare_only)
+    except Exception:
+      if not params.get_bool("ChestnutActive"):
+        raise
+      cloudlog.exception("chestnut failed, falling back to small")
+      params.put_bool("ChestnutActive", False)
+      assert small_model is not None
+      model = small_model
+      if chestnut_state is not None:
+        chestnut_state.big = False
+      run_count = 0
+      model_output = None
    mt2 = time.perf_counter()
    model_execution_time = mt2 - mt1

@@ -524,7 +538,7 @@ def main(demo=False):
      fill_model_msg(drivingdata_send, modelv2_send, model_output, action,
                     publish_state, meta_main.frame_id, meta_extra.frame_id, frame_id,
                     frame_drop_ratio, meta_main.timestamp_eof, model_execution_time, live_calib_seen, meta_constants)
-      modelv2_send.modelV2.big = model.usbgpu
+      modelv2_send.modelV2.big = model.chestnut

      desire_state = modelv2_send.modelV2.meta.desireState
      l_lane_change_prob = desire_state[log.Desire.laneChangeLeft]
@@ -190,8 +190,8 @@ def tmp_path():

 def patch_modeld(monkeypatch):
  def _patch(bundle):
-    monkeypatch.setattr(helpers, 'get_active_bundle', lambda params=None, *, usbgpu=None: bundle)
-    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, usbgpu=None: bundle)
+    monkeypatch.setattr(helpers, 'get_active_bundle', lambda params=None, *, chestnut=None: bundle)
+    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, chestnut=None: bundle)

  return _patch

@@ -59,8 +59,8 @@ class TestFindDrivingPkl(OpenpilotTestCase):
 class TestModelStateCombinedInit(OpenpilotTestCase):
  def test_asserts_when_no_pkl(self, monkeypatch):
    bundle = DummyBundle(models=[], is_20hz=True)
-    monkeypatch.setattr(helpers, 'get_active_bundle', lambda params=None, *, usbgpu=None: bundle)
-    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, usbgpu=None: bundle)
+    monkeypatch.setattr(helpers, 'get_active_bundle', lambda params=None, *, chestnut=None: bundle)
+    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, chestnut=None: bundle)
    with self.assertRaisesRegex(AssertionError, "No driving pkl found"):
      ModelState(cam_w=CAM_W, cam_h=CAM_H)

@@ -0,0 +1,62 @@
+"""
+Copyright (c) 2021-, Haibin Wen, sunnypilot, and a number of other contributors.
+
+This file is part of sunnypilot and is licensed under the MIT License.
+See the LICENSE.md file in the root directory for more details.
+"""
+
+import io
+import requests
+
+from openpilot.common.file_chunker import get_chunk_name
+from openpilot.common.hardware import hw
+from openpilot.common.test import OpenpilotTestCase
+from openpilot.selfdrive.modeld.helpers import dump_oob
+import openpilot.sunnypilot.modeld_v2.modeld as modeld_module
+from openpilot.sunnypilot.modeld_v2.tests import helpers as tests_helpers
+from openpilot.sunnypilot.modeld_v2.tests.helpers import DummyModel, DummyBundle, CAM_W, CAM_H
+from openpilot.sunnypilot.models.fetcher import ModelParser, ModelFetcher
+
+tmp_path = tests_helpers.tmp_path
+
+
+class TestFallback(OpenpilotTestCase):
+  def test_find_dual_model_in_bundle(self, tmp_path, monkeypatch):
+    lebowski_file = 'driving_lebowski.pkl'
+    tsfdo_file = 'driving_tsfdo.pkl'
+    (tmp_path / lebowski_file).write_bytes(b'fkasdjfkljf')
+    (tmp_path / tsfdo_file).write_bytes(b'dskfajklsdjlsfka')
+
+    monkeypatch.setattr(hw.Paths, 'model_root', staticmethod(lambda: str(tmp_path)))
+    big_bundle = DummyBundle(models=[DummyModel('supercombo', lebowski_file)])
+    small_bundle = DummyBundle(models=[DummyModel('supercombo', tsfdo_file)])
+    big_pkl = modeld_module._find_driving_pkl(big_bundle)
+    small_pkl = modeld_module._find_driving_pkl(small_bundle)
+
+    assert big_pkl is not None and lebowski_file in big_pkl
+    assert small_pkl is not None and tsfdo_file in small_pkl
+
+  def test_download_models_and_init_modelstate_fallback(self, tmp_path, monkeypatch):
+    monkeypatch.setattr(hw.Paths, 'model_root', staticmethod(lambda: str(tmp_path)))
+    big_json = requests.get(ModelFetcher.MODEL_URL_CHESTNUT).json()
+    big_bundle = ModelParser.parse_models(big_json)[-1]
+    small_json = requests.get(ModelFetcher.MODEL_URL).json()
+    small_bundle = ModelParser.parse_models(small_json)[-1]
+
+    buf = io.BytesIO()
+    dump_oob(tests_helpers.make_pkl_data(tests_helpers.ARCHETYPES['supercombo_non20hz']), buf)
+    oob_bytes = buf.getvalue()
+
+    for bundle in (big_bundle, small_bundle):
+      artifact = bundle.models[0].artifact
+      for i in range(len(artifact.chunks)):
+        (tmp_path / get_chunk_name(artifact.fileName, i, len(artifact.chunks))).write_bytes(oob_bytes if i == 0 else b"")
+
+    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, chestnut=None: small_bundle)
+    assert modeld_module.ModelState(CAM_W, CAM_H, chestnut=False).chestnut is False
+
+    monkeypatch.setattr(modeld_module, 'get_active_bundle', lambda params=None, *, chestnut=None: big_bundle)
+    try:
+      assert modeld_module.ModelState(CAM_W, CAM_H, chestnut=True).chestnut is True
+    except Exception as e:
+      assert "AMD" in str(e) or "device" in str(e).lower()
@@ -1,16 +1,19 @@
 import argparse
 import os
 import hashlib
+import requests
+import re

 from openpilot.common.basedir import BASEDIR
 from openpilot.selfdrive.ui.ui_state import ui_state
 from openpilot.sunnypilot import get_file_hash
 from openpilot.sunnypilot.models.model_name import DEFAULT_MODEL, DEFAULT_BIG_MODEL
+from openpilot.sunnypilot.models.fetcher import ModelFetcher


 def get_default_model() -> str:
-  show_big_model = (ui_state.usbgpu
-                    and (ui_state.usbgpu_active or ui_state.usbgpu_loading or ui_state.is_offroad()))
+  show_big_model = (ui_state.chestnut_present
+                    and (ui_state.chestnut_active or ui_state.chestnut_loading or ui_state.is_offroad()))

  return DEFAULT_BIG_MODEL if show_big_model else DEFAULT_MODEL

@@ -30,14 +33,29 @@ def update_model_hash():
  print(f"Generated and updated new combined model hash to {MODEL_HASH_PATH}")


+def get_ref_for_name(url: str, name: str) -> str:
+  response = requests.get(url, timeout=10)
+  if response.status_code == 200:
+    bundles = response.json()["bundles"]
+    matching = [b for b in bundles if re.search(name, f"{b['short_name']} {b['display_name']}", re.IGNORECASE)]
+    if matching:
+      return max(matching, key=lambda b: int(b["index"]))["ref"]
+  return ""
+
+
 def update_default_model_names(default_model_name: str, default_big_model_name: str):
  print("[CHANGE DEFAULT MODEL NAMES]")
+  small_ref = get_ref_for_name(ModelFetcher.MODEL_URL, default_model_name)
+  big_ref = get_ref_for_name(ModelFetcher.MODEL_URL_CHESTNUT, default_big_model_name)
+
  with open(DEFAULT_MODEL_NAME_PATH, "w") as f:
    f.write(f'DEFAULT_MODEL = "{default_model_name}"\n')
+    f.write(f'DEFAULT_MODEL_REF = "{small_ref}"\n')
    f.write(f'DEFAULT_BIG_MODEL = "{default_big_model_name}"\n')
+    f.write(f'DEFAULT_BIG_MODEL_REF = "{big_ref}"\n')

-  print(f'New default small model name: "{default_model_name}"')
-  print(f'New default big model name: "{default_big_model_name}"')
+  print(f'New default small model name: "{default_model_name}" (ref: {small_ref})')
+  print(f'New default big model name: "{default_big_model_name}" (ref: {big_ref})')
  print("[DONE]")


@@ -139,11 +139,11 @@ class ModelCache:
 class ModelFetcher:
  """Handles fetching and caching of model data from remote source"""
  MODEL_URL = "https://raw.githubusercontent.com/sunnypilot/sunnypilot-models/refs/heads/gh-pages/docs/driving_models_v21.json"
-  MODEL_URL_USBGPU = "https://raw.githubusercontent.com/sunnypilot/sunnypilot-models/refs/heads/gh-pages/docs/driving_models_usbgpu_v22.json"
+  MODEL_URL_CHESTNUT = "https://raw.githubusercontent.com/sunnypilot/sunnypilot-models/refs/heads/gh-pages/docs/driving_models_chestnut_v22.json"

  MODEL_SOURCES = {
    "qcom": (MODEL_URL, ""),
-    "usbgpu": (MODEL_URL_USBGPU, "_USBGPU"),
+    "chestnut": (MODEL_URL_CHESTNUT, "_Chestnut"),
  }

  def __init__(self, params: Params):
@@ -156,12 +156,12 @@ class ModelFetcher:
    self._refetched: set[str] = set()
    self.params.put("ModelManager_ActiveJson", {
      "qcom": self.MODEL_URL,
-      "usbgpu": self.MODEL_URL_USBGPU,
+      "chestnut": self.MODEL_URL_CHESTNUT,
    }, block=True)

  @staticmethod
  def active_source(chestnut_present: bool) -> str:
-    return "usbgpu" if chestnut_present else "qcom"
+    return "chestnut" if chestnut_present else "qcom"

  def _fetch_and_cache_models(self, source: str) -> list[custom.ModelManagerSP.ModelBundle] | None:
    """Fetches fresh model data from remote and updates cache.
@@ -200,7 +200,7 @@ class ModelFetcher:
  @staticmethod
  def _cache_matches_source(source: str, cached_data: dict) -> bool:
    bundles = cached_data.get("bundles", [])
-    if source == "usbgpu":
+    if source == "chestnut":
      return any(bundle.get("is_big") is True for bundle in bundles)
    return not any(bundle.get("is_big") is True for bundle in bundles)

@@ -261,10 +261,10 @@ def get_cached_bundles(params: Params, source: str) -> list[custom.ModelManagerS


 if __name__ == "__main__":
-  from openpilot.selfdrive.modeld.helpers import usbgpu_present
+  from openpilot.selfdrive.modeld.helpers import chestnut_present
  params = Params()
  model_fetcher = ModelFetcher(params)
-  bundles = model_fetcher.get_bundles_for_source(ModelFetcher.active_source(usbgpu_present()))
+  bundles = model_fetcher.get_bundles_for_source(ModelFetcher.active_source(chestnut_present()))
  for bundle in bundles:
    for model in bundle.models:
      model_overrides = {override.key: override.value for override in bundle.overrides}
@@ -16,7 +16,7 @@ from openpilot.common.params import Params
 from openpilot.common.swaglog import cloudlog
 from openpilot.sunnypilot.models.constants import Meta, MetaSimPose, MetaTombRaider
 from openpilot.common.hardware.hw import Paths
-from openpilot.selfdrive.modeld.helpers import usbgpu_present
+from openpilot.selfdrive.modeld.helpers import chestnut_present

 # SET ME TO THE EXACT JSON VERSION WE SET IN SUNNYPILOT_MODELS REPO
 REQUIRED_JSON_VERSION = 18
@@ -27,7 +27,7 @@ ModelManager = custom.ModelManagerSP

 ACTIVE_BUNDLE_KEYS = {
  "qcom": "ModelManager_ActiveBundle",
-  "usbgpu": "ModelManager_ActiveBundleUSBGPU",
+  "chestnut": "ModelManager_ActiveBundleChestnut",
 }
 _LAST_VALIDATED_RAW: dict[str, dict | None] = {}

@@ -126,20 +126,20 @@ def get_selected_bundle(params: Params | None = None, source: str = "qcom") -> "
  return _parse_active_bundle(params.get(ACTIVE_BUNDLE_KEYS[source]))


-def get_active_source(usbgpu: bool | None = None, usbgpu_active: bool | None = None,
-                      usbgpu_loading: bool | None = None, offroad: bool | None = None) -> str:
-  if usbgpu is None:
-    usbgpu = usbgpu_present()
-  state_valid = usbgpu_active is not None or usbgpu_loading is not None or offroad is not None
-  big_active = usbgpu and (not state_valid or usbgpu_active or usbgpu_loading or offroad)
-  return "usbgpu" if big_active else "qcom"
+def get_active_source(chestnut: bool | None = None, chestnut_active: bool | None = None,
+                      chestnut_loading: bool | None = None, offroad: bool | None = None) -> str:
+  if chestnut is None:
+    chestnut = chestnut_present()
+  state_valid = chestnut_active is not None or chestnut_loading is not None or offroad is not None
+  big_active = chestnut and (not state_valid or chestnut_active or chestnut_loading or offroad)
+  return "chestnut" if big_active else "qcom"


-def get_active_bundle(params: Params | None = None, *, usbgpu: bool | None = None) -> "custom.ModelManagerSP.ModelBundle | None":
+def get_active_bundle(params: Params | None = None, *, chestnut: bool | None = None) -> "custom.ModelManagerSP.ModelBundle | None":
  # no cross-slot fallback: an empty active slot means the hardware default, which
  # only stock modeld can run - modeld_v2 requires a real bundle
  params = params or Params()
-  return get_selected_bundle(params, get_active_source(usbgpu=usbgpu))
+  return get_selected_bundle(params, get_active_source(chestnut=chestnut))


 def resolve_bundle_by_ref(
@@ -40,7 +40,7 @@ class ModelManagerSP:
    self.available_models: list[custom.ModelManagerSP.ModelBundle] = []
    self.source_models: dict[str, list[custom.ModelManagerSP.ModelBundle]] = {}
    self.selected_bundle: custom.ModelManagerSP.ModelBundle = None
-    self.active_bundle: custom.ModelManagerSP.ModelBundle = get_active_bundle(self.params, usbgpu=self.chestnut_present)
+    self.active_bundle: custom.ModelManagerSP.ModelBundle = get_active_bundle(self.params, chestnut=self.chestnut_present)
    self._chunk_size = 128 * 1000  # 128 KB chunks
    self._download_start_times: dict[str, float] = {}  # Track start time per model
    self._download_ref: bytes | str | None = None
@@ -280,7 +280,7 @@ class ModelManagerSP:
        raise DownloadCancelled("Download cancelled")
      self.selected_bundle.status = custom.ModelManagerSP.DownloadStatus.downloaded
      self.params.put(ACTIVE_BUNDLE_KEYS[source], model_bundle.to_dict(), block=True)
-      self.active_bundle = get_active_bundle(self.params, usbgpu=self.chestnut_present)
+      self.active_bundle = get_active_bundle(self.params, chestnut=self.chestnut_present)

    except Exception:
      if self.selected_bundle is not None:
@@ -326,7 +326,13 @@ class ModelManagerSP:
        self.source_models = {source: self.model_fetcher.get_bundles_for_source(source) for source in ModelFetcher.MODEL_SOURCES}
        self.available_models = self.source_models[ModelFetcher.active_source(self.chestnut_present)]
        validate_active_bundles(self.params, self.source_models)
-        self.active_bundle = get_active_bundle(self.params, usbgpu=self.chestnut_present)
+        self.active_bundle = get_active_bundle(self.params, chestnut=self.chestnut_present)
+
+        if get_selected_bundle(self.params, "chestnut") is not None and get_selected_bundle(self.params, "qcom") is None:
+          if self.params.get("ModelManager_DownloadRef") is None:
+            from openpilot.sunnypilot.models.model_name import DEFAULT_MODEL_REF
+            if DEFAULT_MODEL_REF:
+              self.params.put("ModelManager_DownloadRef", DEFAULT_MODEL_REF)

        self._process_download_requests()

@@ -1,2 +1,4 @@
 DEFAULT_MODEL = "CD210"
+DEFAULT_MODEL_REF = "5b6436a90cf6902b8aaa71c2b6f3d7164d8ae391"
 DEFAULT_BIG_MODEL = "Lebowski"
+DEFAULT_BIG_MODEL_REF = "fa0c6876d3cf070e91e25e5353ceadc68a5b3285"
@@ -392,7 +392,7 @@ class TestManagerDownload(ManagerDownloadTestBase):
      asyncio.run(self.manager._download_bundle(self._bundle, self.dest, "qcom"))

      assert "ModelManager_ActiveBundle" in store, "qcom download must write the qcom slot"
-      assert "ModelManager_ActiveBundleUSBGPU" not in store, "qcom download must not touch the usbgpu slot"
+      assert "ModelManager_ActiveBundleChestnut" not in store, "qcom download must not touch the chestnut slot"
      assert self.manager.selected_bundle.status == custom.ModelManagerSP.DownloadStatus.downloaded
      assert self.manager.active_bundle is not None and self.manager.active_bundle.ref == "test-ref"
      assert self.manager.active_bundle.status == custom.ModelManagerSP.DownloadStatus.downloaded
@@ -401,18 +401,18 @@ class TestManagerDownload(ManagerDownloadTestBase):
      assert missing == [], f"chunks missing from the cache: {missing}"
    self.run_with_server(body)

-  def test_download_writes_usbgpu_slot(self):
-    """A download resolved to the usbgpu source writes the usbgpu active bundle slot only."""
+  def test_download_writes_chestnut_slot(self):
+    """A download resolved to the chestnut source writes the chestnut active bundle slot only."""
    def body():
      self.make_artifact(chunked=True)
      self._bundle.ref = "big-ref"
      self._bundle.minimumSelectorVersion = 18
      params, store = self._make_params_with_store()
      self.manager.params = params
-      asyncio.run(self.manager._download_bundle(self._bundle, self.dest, "usbgpu"))
+      asyncio.run(self.manager._download_bundle(self._bundle, self.dest, "chestnut"))

-      assert "ModelManager_ActiveBundleUSBGPU" in store, "usbgpu download must write the usbgpu slot"
-      assert "ModelManager_ActiveBundle" not in store, "usbgpu download must not touch the qcom slot"
+      assert "ModelManager_ActiveBundleChestnut" in store, "chestnut download must write the chestnut slot"
+      assert "ModelManager_ActiveBundle" not in store, "chestnut download must not touch the qcom slot"
      assert self.manager.selected_bundle.status == custom.ModelManagerSP.DownloadStatus.downloaded
    self.run_with_server(body)

@@ -447,20 +447,20 @@ class TestResolveBundleByRef(OpenpilotTestCase):

  def test_qcom_ref_resolves_to_qcom_slot(self):
    small = self._bundle("small")
-    assert resolve_bundle_by_ref("small", {"qcom": [small], "usbgpu": []}) == (small, "qcom")
+    assert resolve_bundle_by_ref("small", {"qcom": [small], "chestnut": []}) == (small, "qcom")

-  def test_usbgpu_ref_resolves_to_usbgpu_slot(self):
+  def test_chestnut_ref_resolves_to_chestnut_slot(self):
    big = self._bundle("big")
-    assert resolve_bundle_by_ref("big", {"qcom": [], "usbgpu": [big]}) == (big, "usbgpu")
+    assert resolve_bundle_by_ref("big", {"qcom": [], "chestnut": [big]}) == (big, "chestnut")

  def test_unknown_ref_returns_none(self):
-    source_bundles = {"qcom": [self._bundle("small")], "usbgpu": []}
+    source_bundles = {"qcom": [self._bundle("small")], "chestnut": []}
    assert resolve_bundle_by_ref("nope", source_bundles) is None


 def manifest_bundle(short_name: str, ref: str, index: int = 0, is_big: bool = False) -> dict:
  """Minimal manifest bundle dict, version-compatible (no chunks to avoid disk side effects).
-  Big (usbgpu) bundles carry `is_big: true` in the manifest JSON."""
+  Big (chestnut) bundles carry `is_big: true` in the manifest JSON."""
  return {
    "index": index,
    "short_name": short_name,
@@ -489,15 +489,15 @@ class TestModelFetcherSources(OpenpilotTestCase):
  """Both manifests are always maintained: get_bundles_for_source exposes either
  source by name, and active_source picks which one matches the attached hardware."""

-  def _make_params(self, qcom_manifest, usbgpu_manifest):
+  def _make_params(self, qcom_manifest, chestnut_manifest):
    params = mock.MagicMock()

    def get(key):
      if key == "ModelManager_ModelsCache":
        return qcom_manifest
-      if key == "ModelManager_ModelsCache_USBGPU":
-        return usbgpu_manifest
-      if key in ("ModelManager_LastSyncTime", "ModelManager_LastSyncTime_USBGPU"):
+      if key == "ModelManager_ModelsCache_Chestnut":
+        return chestnut_manifest
+      if key in ("ModelManager_LastSyncTime", "ModelManager_LastSyncTime_Chestnut"):
        return fresh_sync_time()
      return None

@@ -506,14 +506,14 @@ class TestModelFetcherSources(OpenpilotTestCase):

  def test_active_source_follows_chestnut_presence(self):
    assert ModelFetcher.active_source(False) == "qcom"
-    assert ModelFetcher.active_source(True) == "usbgpu"
+    assert ModelFetcher.active_source(True) == "chestnut"

  def test_get_bundles_for_source_returns_each_source(self):
    params = self._make_params({"bundles": [manifest_bundle("small", "aaa")]},
                               {"bundles": [manifest_bundle("big", "bbb", is_big=True)]})
    fetcher = ModelFetcher(params)
    assert [bundle.ref for bundle in fetcher.get_bundles_for_source("qcom")] == ["aaa"]
-    assert [bundle.ref for bundle in fetcher.get_bundles_for_source("usbgpu")] == ["bbb"]
+    assert [bundle.ref for bundle in fetcher.get_bundles_for_source("chestnut")] == ["bbb"]

  def test_get_bundles_for_source_unknown(self):
    assert ModelFetcher(mock.MagicMock()).get_bundles_for_source("bogus") == []
@@ -522,16 +522,16 @@ class TestModelFetcherSources(OpenpilotTestCase):
    params = self._make_params({"bundles": [manifest_bundle("small", "aaa")]},
                               {"bundles": [manifest_bundle("big", "bbb", is_big=True)]})
    qcom_bundles = get_cached_bundles(params, "qcom")
-    usbgpu_bundles = get_cached_bundles(params, "usbgpu")
+    chestnut_bundles = get_cached_bundles(params, "chestnut")
    assert [b.ref for b in qcom_bundles] == ["aaa"]
-    assert [b.ref for b in usbgpu_bundles] == ["bbb"]
+    assert [b.ref for b in chestnut_bundles] == ["bbb"]
    assert qcom_bundles[0].displayName == "SMALL"

  def test_get_cached_bundles_empty_when_missing(self):
    params = mock.MagicMock()
    params.get.return_value = None
    assert get_cached_bundles(params, "qcom") == []
-    assert get_cached_bundles(params, "usbgpu") == []
+    assert get_cached_bundles(params, "chestnut") == []

  def test_get_cached_bundles_unknown_source(self):
    assert get_cached_bundles(mock.MagicMock(), "bogus") == []
@@ -543,27 +543,27 @@ class TestModelFetcherSources(OpenpilotTestCase):
    assert active_json_calls, "expected ModelManager_ActiveJson to be written"
    assert active_json_calls[-1].args[1] == {
      "qcom": ModelFetcher.MODEL_URL,
-      "usbgpu": ModelFetcher.MODEL_URL_USBGPU,
+      "chestnut": ModelFetcher.MODEL_URL_CHESTNUT,
    }



 class TestSourceCacheIntegrity(OpenpilotTestCase):
  """Each source's cached manifest must contain only that source's models; the
-  `is_big` flag in the JSON marks the big (usbgpu) models. A mismatched cache is
+  `is_big` flag in the JSON marks the big (chestnut) models. A mismatched cache is
  legacy data from before the per-source split (the active manifest was cached
  under the unsuffixed key regardless of hardware) and is refetched. This
  replaces the old one-time bundle migration."""

-  def _make_params(self, qcom_manifest, usbgpu_manifest):
+  def _make_params(self, qcom_manifest, chestnut_manifest):
    params = mock.MagicMock()

    def get(key):
      if key == "ModelManager_ModelsCache":
        return qcom_manifest
-      if key == "ModelManager_ModelsCache_USBGPU":
-        return usbgpu_manifest
-      if key in ("ModelManager_LastSyncTime", "ModelManager_LastSyncTime_USBGPU"):
+      if key == "ModelManager_ModelsCache_Chestnut":
+        return chestnut_manifest
+      if key in ("ModelManager_LastSyncTime", "ModelManager_LastSyncTime_Chestnut"):
        return fresh_sync_time()
      return None

@@ -584,13 +584,13 @@ class TestSourceCacheIntegrity(OpenpilotTestCase):
      bundles = fetcher.get_bundles_for_source("qcom")
    assert [bundle.ref for bundle in bundles] == ["aaa"]

-  def test_usbgpu_cache_without_big_models_is_refetched(self):
+  def test_chestnut_cache_without_big_models_is_refetched(self):
    params = self._make_params({"bundles": [manifest_bundle("small", "aaa")]},
                               {"bundles": [manifest_bundle("big2", "ccc")]})
    fetcher = ModelFetcher(params)
    fetched = self._fetched(manifest_bundle("big", "bbb", is_big=True))
    with mock.patch.object(fetcher, "_fetch_and_cache_models", return_value=fetched):
-      bundles = fetcher.get_bundles_for_source("usbgpu")
+      bundles = fetcher.get_bundles_for_source("chestnut")
    assert [bundle.ref for bundle in bundles] == ["bbb"]

  def test_matching_caches_are_used_without_fetch(self):
@@ -599,7 +599,7 @@ class TestSourceCacheIntegrity(OpenpilotTestCase):
    fetcher = ModelFetcher(params)
    with mock.patch.object(fetcher, "_fetch_and_cache_models", side_effect=AssertionError("cache should be used")):
      assert [bundle.ref for bundle in fetcher.get_bundles_for_source("qcom")] == ["aaa"]
-      assert [bundle.ref for bundle in fetcher.get_bundles_for_source("usbgpu")] == ["bbb"]
+      assert [bundle.ref for bundle in fetcher.get_bundles_for_source("chestnut")] == ["bbb"]

  def test_stale_version_cache_is_refetched(self):
    """A source-matching cache whose bundles are all filtered by the selector version
@@ -660,28 +660,28 @@ class TestActiveBundleValidation(OpenpilotTestCase):
      bundle.runner = runner
    return bundle.to_dict()

-  def _params(self, qcom=None, usbgpu=None):
+  def _params(self, qcom=None, chestnut=None):
    params = mock.MagicMock()

    def get(key, *args, **kwargs):
-      return {"ModelManager_ActiveBundle": qcom, "ModelManager_ActiveBundleUSBGPU": usbgpu}.get(key)
+      return {"ModelManager_ActiveBundle": qcom, "ModelManager_ActiveBundleChestnut": chestnut}.get(key)

    params.get.side_effect = get
    return params

  def test_empty_catalog_does_not_reset_slot(self):
    params = self._params(qcom=self._raw_bundle("small"))
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=False):
-      validate_active_bundles(params, {"qcom": [], "usbgpu": []})
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=False):
+      validate_active_bundles(params, {"qcom": [], "chestnut": []})
    params.remove.assert_not_called()

  def test_reset_recomputes_runner_from_surviving_slot(self):
    tinygrad = int(custom.ModelManagerSP.Runner.tinygrad)
    big_raw = self._raw_bundle("big", runner=tinygrad)
-    params = self._params(qcom=self._raw_bundle("gone"), usbgpu=big_raw)
+    params = self._params(qcom=self._raw_bundle("gone"), chestnut=big_raw)
    catalog = {"qcom": [custom.ModelManagerSP.ModelBundle(**self._raw_bundle("other"))],
-               "usbgpu": [custom.ModelManagerSP.ModelBundle(**big_raw)]}
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=True):
+               "chestnut": [custom.ModelManagerSP.ModelBundle(**big_raw)]}
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=True):
      validate_active_bundles(params, catalog)
    params.remove.assert_called_once_with("ModelManager_ActiveBundle")
    runner_puts = [call for call in params.put.call_args_list if call.args[0] == "ModelRunnerTypeCache"]
@@ -689,7 +689,7 @@ class TestActiveBundleValidation(OpenpilotTestCase):


 class TestActiveBundleSelection(OpenpilotTestCase):
-  """The effective active bundle is the active source's slot: usbgpu when a GPU is
+  """The effective active bundle is the active source's slot: chestnut when a GPU is
  present, qcom otherwise. An empty active slot means the hardware default (stock
  runner), never the other slot's pick - modeld_v2 requires a real bundle."""

@@ -700,37 +700,37 @@ class TestActiveBundleSelection(OpenpilotTestCase):
    bundle.minimumSelectorVersion = 18
    return bundle.to_dict()

-  def _params(self, qcom=None, usbgpu=None):
+  def _params(self, qcom=None, chestnut=None):
    params = mock.MagicMock()

    def get(key, *args, **kwargs):
      if key == "ModelManager_ActiveBundle":
        return qcom
-      if key == "ModelManager_ActiveBundleUSBGPU":
-        return usbgpu
+      if key == "ModelManager_ActiveBundleChestnut":
+        return chestnut
      return None

    params.get.side_effect = get
    return params

  def test_selected_bundle_is_per_slot(self):
-    params = self._params(qcom=self._raw_bundle("small"), usbgpu=self._raw_bundle("big"))
+    params = self._params(qcom=self._raw_bundle("small"), chestnut=self._raw_bundle("big"))
    assert get_selected_bundle(params, "qcom").ref == "small"
-    assert get_selected_bundle(params, "usbgpu").ref == "big"
+    assert get_selected_bundle(params, "chestnut").ref == "big"

  def test_no_gpu_uses_qcom_slot(self):
-    params = self._params(qcom=self._raw_bundle("small"), usbgpu=self._raw_bundle("big"))
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=False):
+    params = self._params(qcom=self._raw_bundle("small"), chestnut=self._raw_bundle("big"))
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=False):
      assert get_active_bundle(params).ref == "small"

-  def test_gpu_uses_usbgpu_slot(self):
-    params = self._params(qcom=self._raw_bundle("small"), usbgpu=self._raw_bundle("big"))
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=True):
+  def test_gpu_uses_chestnut_slot(self):
+    params = self._params(qcom=self._raw_bundle("small"), chestnut=self._raw_bundle("big"))
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=True):
      assert get_active_bundle(params).ref == "big"

  def test_gpu_without_big_selection_is_hardware_default(self):
-    params = self._params(qcom=self._raw_bundle("small"), usbgpu=None)
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=True):
+    params = self._params(qcom=self._raw_bundle("small"), chestnut=None)
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=True):
      assert get_active_bundle(params) is None


@@ -748,36 +748,36 @@ class TestEffectiveSource(OpenpilotTestCase):
    return bundle.to_dict()

  def test_runtime_no_gpu(self):
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=False):
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=False):
      assert get_active_source() == "qcom"

  def test_runtime_gpu_present(self):
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=True):
-      assert get_active_source() == "usbgpu"
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=True):
+      assert get_active_source() == "chestnut"

  def test_display_offroad_gpu_present_shows_big(self):
-    assert get_active_source(usbgpu=True, usbgpu_active=False, usbgpu_loading=False, offroad=True) == "usbgpu"
+    assert get_active_source(chestnut=True, chestnut_active=False, chestnut_loading=False, offroad=True) == "chestnut"

  def test_display_onroad_gpu_loading_shows_big(self):
-    assert get_active_source(usbgpu=True, usbgpu_active=False, usbgpu_loading=True, offroad=False) == "usbgpu"
+    assert get_active_source(chestnut=True, chestnut_active=False, chestnut_loading=True, offroad=False) == "chestnut"

  def test_display_onroad_gpu_active_shows_big(self):
-    assert get_active_source(usbgpu=True, usbgpu_active=True, usbgpu_loading=False, offroad=False) == "usbgpu"
+    assert get_active_source(chestnut=True, chestnut_active=True, chestnut_loading=False, offroad=False) == "chestnut"

  def test_display_onroad_gpu_idle_shows_small(self):
-    assert get_active_source(usbgpu=True, usbgpu_active=False, usbgpu_loading=False, offroad=False) == "qcom"
+    assert get_active_source(chestnut=True, chestnut_active=False, chestnut_loading=False, offroad=False) == "qcom"

  def test_display_active_none_is_idle(self):
-    assert get_active_source(usbgpu=True, usbgpu_active=None, usbgpu_loading=False, offroad=False) == "qcom"
+    assert get_active_source(chestnut=True, chestnut_active=None, chestnut_loading=False, offroad=False) == "qcom"

  def test_active_bundle_follows_source(self):
    params = mock.MagicMock()
    params.get.side_effect = lambda key: {"ModelManager_ActiveBundle": self._raw_bundle("small"),
-                                          "ModelManager_ActiveBundleUSBGPU": self._raw_bundle("big")}.get(key)
-    with mock.patch("openpilot.sunnypilot.models.helpers.usbgpu_present", return_value=False):
+                                          "ModelManager_ActiveBundleChestnut": self._raw_bundle("big")}.get(key)
+    with mock.patch("openpilot.sunnypilot.models.helpers.chestnut_present", return_value=False):
      assert get_active_bundle(params).ref == "small"
-    assert get_selected_bundle(params, get_active_source(usbgpu=True, usbgpu_active=False,
-                                                         usbgpu_loading=False, offroad=True)).ref == "big"
+    assert get_selected_bundle(params, get_active_source(chestnut=True, chestnut_active=False,
+                                                         chestnut_loading=False, offroad=True)).ref == "big"


@unittest.skipUnless(os.environ.get('RUN_INTEGRATION_TESTS'), 'requires external network')
@@ -252,4 +252,12 @@ EVENTS_SP: dict[int, dict[str, Alert | AlertCallbackType]] = {
      AlertStatus.userPrompt, AlertSize.small,
      Priority.LOW, VisualAlert.none, AudibleAlert.prompt, 0.1),
  },
+
+  EventNameSP.bigModelReady: {
+    ET.PERMANENT: Alert(
+      "Big Model Ready",
+      "",
+      AlertStatus.normal, AlertSize.small,
+      Priority.LOW, VisualAlert.none, AudibleAlert.prompt, 2.),
+  },
 }
@@ -183,7 +183,7 @@ def getParamsMetadata() -> str:
    schema["capability_labels"] = CAPABILITY_LABELS
    schema["default_model"] = DEFAULT_MODEL
    schema["default_big_model"] = DEFAULT_BIG_MODEL
-    schema["usbgpu_active"] = params.get_bool("UsbGpuActive")
+    schema["chestnut_active"] = params.get_bool("ChestnutActive")
    raw = json.dumps(schema, separators=(",", ":")).encode("utf-8")
    return base64.b64encode(gzip.compress(raw)).decode("utf-8")
  except Exception:
@@ -65,7 +65,7 @@ def sp_stats(end_event):
    'MadsSteeringMode',
    'MadsUnifiedEngagementMode',
    'ModelManager_ActiveBundle',
-    'ModelManager_ActiveBundleUSBGPU',
+    'ModelManager_ActiveBundleChestnut',
    'ModelManager_Favs',
    'EnableSunnylinkUploader',
    'SunnylinkEnabled',
@@ -89,12 +89,16 @@ def _migrate_model_bundle_slots(_params):
  # ActiveBundle. Seed both slots; validation drops whichever does not match
  # its own manifest.
  try:
-    if _params.get("ModelManager_ActiveBundleUSBGPU") is not None:
+    if _params.get("ModelManager_ActiveBundleChestnut") is not None:
+      return
+    if (chestnut_bundle := _params.get("ModelManager_ActiveBundleUSBGPU")) is not None:
+      _params.put("ModelManager_ActiveBundleChestnut", chestnut_bundle, block=True)
+      cloudlog.info("params_migration: seeded ModelManager_ActiveBundleChestnut from ModelManager_ActiveBundleUSBGPU")
      return
    if (bundle := _params.get("ModelManager_ActiveBundle")) is None:
      return
-    _params.put("ModelManager_ActiveBundleUSBGPU", bundle, block=True)
-    cloudlog.info("params_migration: seeded ModelManager_ActiveBundleUSBGPU from ModelManager_ActiveBundle")
+    _params.put("ModelManager_ActiveBundleChestnut", bundle, block=True)
+    cloudlog.info("params_migration: seeded ModelManager_ActiveBundleChestnut from ModelManager_ActiveBundle")
  except Exception as e:
    cloudlog.exception(f"Error migrating model bundle slots: {e}")

@@ -136,5 +140,5 @@ def run_migration(_params):
  # seed TeslaMadsScreenButton for existing Tesla installs
  _migrate_tesla_mads_screen_button(_params)

-  # seed the usbgpu model slot from the pre-split single slot
+  # seed the chestnut model slot from the pre-split single slot
  _migrate_model_bundle_slots(_params)
@@ -15,22 +15,22 @@ class TestModelBundleSlotMigration(OpenpilotTestCase):
  The migration seeds both slots; per-source validation later drops whichever does not
  match its own manifest."""

-  def test_seeds_usbgpu_slot_from_active_bundle(self):
+  def test_seeds_chestnut_slot_from_active_bundle(self):
    params = Params()
    bundle = {"ref": "big", "minimumSelectorVersion": 18}
    params.put("ModelManager_ActiveBundle", bundle, block=True)
    _migrate_model_bundle_slots(params)
-    assert params.get("ModelManager_ActiveBundleUSBGPU") == bundle
+    assert params.get("ModelManager_ActiveBundleChestnut") == bundle
    assert params.get("ModelManager_ActiveBundle") == bundle

-  def test_noop_when_usbgpu_slot_already_set(self):
+  def test_noop_when_chestnut_slot_already_set(self):
    params = Params()
    params.put("ModelManager_ActiveBundle", {"ref": "small"}, block=True)
-    params.put("ModelManager_ActiveBundleUSBGPU", {"ref": "big"}, block=True)
+    params.put("ModelManager_ActiveBundleChestnut", {"ref": "big"}, block=True)
    _migrate_model_bundle_slots(params)
-    assert params.get("ModelManager_ActiveBundleUSBGPU") == {"ref": "big"}
+    assert params.get("ModelManager_ActiveBundleChestnut") == {"ref": "big"}

  def test_noop_when_no_selection(self):
    params = Params()
    _migrate_model_bundle_slots(params)
-    assert params.get("ModelManager_ActiveBundleUSBGPU") is None
+    assert params.get("ModelManager_ActiveBundleChestnut") is None
@@ -16,7 +16,7 @@ from openpilot.common.utils import strip_deprecated_keys
 from openpilot.common.filter_simple import FirstOrderFilter
 from openpilot.common.params import Params
 from openpilot.common.realtime import DT_HW
-from openpilot.selfdrive.modeld.helpers import MODELS_DIR, usbgpu_compiled
+from openpilot.selfdrive.modeld.helpers import MODELS_DIR, chestnut_compiled
 from openpilot.selfdrive.selfdrived.alertmanager import set_offroad_alert
 from openpilot.common.hardware import HARDWARE, COMMA_HARDWARE
 from openpilot.common.basedir import BASEDIR
@@ -239,7 +239,7 @@ def hardware_thread(end_event, hw_queue) -> None:

  fan_controller = FanController(int(1./DT_HW))
  chestnut = Chestnut()
-  big_model_available = (MODELS_DIR / 'big_driving_supercombo.onnx').is_file() or usbgpu_compiled()
+  big_model_available = (MODELS_DIR / 'big_driving_supercombo.onnx').is_file() or chestnut_compiled()

  while not end_event.is_set():
    sm.update(PANDA_STATES_TIMEOUT)