diff --git a/launch_env.sh b/launch_env.sh
index 3ad10c881..ff05fc7d0 100755
--- a/launch_env.sh
+++ b/launch_env.sh
@@ -21,7 +21,7 @@ fi
 export QCOM_PRIORITY=12
 
 if [ -z "$AGNOS_VERSION" ]; then
-  export AGNOS_VERSION="12.8.16"
+  export AGNOS_VERSION="12.8.17"
 fi
 
 export STAGING_ROOT="/data/safe_staging"
diff --git a/system/hardware/tici/agnos.json b/system/hardware/tici/agnos.json
index ce4bce3e9..00f6c017a 100644
--- a/system/hardware/tici/agnos.json
+++ b/system/hardware/tici/agnos.json
@@ -67,9 +67,9 @@
   },
   {
     "name": "system",
-    "url": "https://www.dropbox.com/scl/fi/uglf3j1ne3pqtlx8j4mzp/system2.img.xz?rlkey=t1dp8rmyv6kuiyagy4p02ah6q&st=iai09tjz&dl=1",
-    "hash": "06641f9fb602e6b046d1a619cc43dbaa724ff5c3700a32f1ef6677e40146359e",
-    "hash_raw": "06641f9fb602e6b046d1a619cc43dbaa724ff5c3700a32f1ef6677e40146359e",
+    "url": "https://www.dropbox.com/scl/fi/gjhc393yvcza4etsv67us/system3.img.xz?rlkey=yrrwvlw2tljrwu5ullicc1oot&st=9d6ptx4x&dl=1",
+    "hash": "f144e595f907b06b7d583c72563358f49567817de5dfa4f07207e1aeab9af7fd",
+    "hash_raw": "f144e595f907b06b7d583c72563358f49567817de5dfa4f07207e1aeab9af7fd",
     "size": 5368709120,
     "sparse": false,
     "full_check": false,
diff --git a/system/ui/tests/test_updater.py b/system/ui/tests/test_updater.py
new file mode 100644
index 000000000..700b77d8c
--- /dev/null
+++ b/system/ui/tests/test_updater.py
@@ -0,0 +1,53 @@
+import importlib
+import sys
+import types
+from unittest.mock import patch
+
+import pytest
+
+
+@pytest.fixture
+def updater_module(monkeypatch):
+  hardware = types.ModuleType("openpilot.system.hardware")
+  hardware.HARDWARE = types.SimpleNamespace(get_device_type=lambda: "tici")
+  monkeypatch.setitem(sys.modules, "openpilot.system.hardware", hardware)
+  sys.modules.pop("openpilot.system.ui.updater", None)
+  module = importlib.import_module("openpilot.system.ui.updater")
+  yield module
+  sys.modules.pop("openpilot.system.ui.updater", None)
+
+
+def test_device_tree_tici_uses_big_ui(updater_module):
+  with patch.object(updater_module, "_device_tree_device_type", return_value="tici"), \
+       patch.object(updater_module, "_framebuffer_size", return_value=(536, 240)), \
+       patch.object(updater_module, "_reported_device_type", return_value="mici"):
+    assert updater_module._ui_device_type() == "tici"
+
+
+def test_device_tree_tizi_uses_big_ui(updater_module):
+  with patch.object(updater_module, "_device_tree_device_type", return_value="tizi"), \
+       patch.object(updater_module, "_framebuffer_size", return_value=(536, 240)), \
+       patch.object(updater_module, "_reported_device_type", return_value="mici"):
+    assert updater_module._ui_device_type() == "tizi"
+
+
+@pytest.mark.parametrize("device_tree_type", ["mici", "comma 4", "comma four"])
+def test_non_tici_device_tree_uses_small_ui(updater_module, device_tree_type):
+  with patch.object(updater_module, "_device_tree_device_type", return_value=device_tree_type), \
+       patch.object(updater_module, "_framebuffer_size", return_value=(2160, 1080)), \
+       patch.object(updater_module, "_reported_device_type", return_value="tici"):
+    assert updater_module._ui_device_type() == "mici"
+
+
+def test_small_framebuffer_uses_small_ui_without_device_tree(updater_module):
+  with patch.object(updater_module, "_device_tree_device_type", return_value=None), \
+       patch.object(updater_module, "_framebuffer_size", return_value=(536, 240)), \
+       patch.object(updater_module, "_reported_device_type", return_value="tici"):
+    assert updater_module._ui_device_type() == "mici"
+
+
+def test_reported_tici_used_when_no_other_signal(updater_module):
+  with patch.object(updater_module, "_device_tree_device_type", return_value=None), \
+       patch.object(updater_module, "_framebuffer_size", return_value=None), \
+       patch.object(updater_module, "_reported_device_type", return_value="tici"):
+    assert updater_module._ui_device_type() == "tici"
diff --git a/system/ui/updater.py b/system/ui/updater.py
index a894dd18a..6421c7701 100755
--- a/system/ui/updater.py
+++ b/system/ui/updater.py
@@ -3,6 +3,27 @@ from pathlib import Path
 
 from openpilot.system.hardware import HARDWARE
 
+BIG_UI_DEVICE_TYPES = ("tici", "tizi")
+SMALL_UI_DEVICE_TYPE = "mici"
+
+
+def _normalize_device_type(raw: str) -> str:
+  device_type = raw.replace("\x00", "").strip().lower()
+  if "comma " in device_type:
+    device_type = device_type.rsplit("comma ", 1)[-1].strip()
+  return device_type
+
+
+def _device_tree_device_type() -> str | None:
+  model_path = Path("/sys/firmware/devicetree/base/model")
+  if not model_path.is_file():
+    return None
+
+  try:
+    return _normalize_device_type(model_path.read_text(encoding="utf-8", errors="ignore"))
+  except Exception:
+    return None
+
 
 def _framebuffer_size() -> tuple[int, int] | None:
   fb_path = Path("/sys/class/graphics/fb0/virtual_size")
@@ -17,12 +38,40 @@ def _framebuffer_size() -> tuple[int, int] | None:
     return None
 
 
+def _reported_device_type() -> str | None:
+  try:
+    return _normalize_device_type(HARDWARE.get_device_type())
+  except Exception:
+    return None
+
+
 def _ui_device_type() -> str:
-  reported_type = HARDWARE.get_device_type()
+  # AGNOS' baked-in updater can run before the StarPilot wrapper gets a chance to
+  # route mici devices through the small UI. Trust the device tree first and only
+  # allow known large-screen devices to select the tici updater.
+  device_tree_type = _device_tree_device_type()
+  if device_tree_type in BIG_UI_DEVICE_TYPES:
+    return device_tree_type
+  if device_tree_type:
+    return SMALL_UI_DEVICE_TYPE
+
   fb_size = _framebuffer_size()
   if fb_size is not None and max(fb_size) < 1000:
-    return "mici"
-  return reported_type
+    return SMALL_UI_DEVICE_TYPE
+
+  reported_type = _reported_device_type()
+  if reported_type in BIG_UI_DEVICE_TYPES:
+    return reported_type
+  return SMALL_UI_DEVICE_TYPE
+
+
+def _patch_hardware_device_type(device_type: str) -> None:
+  HARDWARE.get_device_type = lambda: device_type
+  try:
+    import openpilot.system.hardware.tici.hardware as tici_hardware
+    tici_hardware.get_device_type = lambda: device_type
+  except Exception:
+    pass
 
 
 def main():
@@ -30,9 +79,9 @@ def main():
 
   # The updater imports application sizing during module import, so patch the
   # hardware probe before importing either UI implementation.
-  HARDWARE.get_device_type = lambda: device_type
+  _patch_hardware_device_type(device_type)
 
-  if device_type in ("tici", "tizi"):
+  if device_type in BIG_UI_DEVICE_TYPES:
     import openpilot.system.ui.tici_updater as updater_impl
   else:
     import openpilot.system.ui.mici_updater as updater_impl
diff --git a/tools/agnos/patch_system_reset_image.py b/tools/agnos/patch_system_reset_image.py
index 8ed3d9880..017832ca3 100644
--- a/tools/agnos/patch_system_reset_image.py
+++ b/tools/agnos/patch_system_reset_image.py
@@ -784,6 +784,11 @@ def patch_updater_zipapp(original: bytes) -> bytes:
         if payload != replacement:
           payload = replacement
           changed = True
+      elif info.filename == APPLICATION_ENTRY_IN_ZIPAPP:
+        patched_payload = patch_application_script(payload)
+        if patched_payload != payload:
+          payload = patched_payload
+          changed = True
 
       new_info = zipfile.ZipInfo(info.filename, info.date_time)
       new_info.compress_type = zipfile.ZIP_DEFLATED
@@ -891,9 +896,10 @@ def updater_zipapp_has_expected_content(data: bytes) -> bool:
   with zipfile.ZipFile(BytesIO(zip_payload), "r") as z:
     try:
       updater_script = z.read(UPDATER_ENTRY_IN_ZIPAPP)
+      app_script = z.read(APPLICATION_ENTRY_IN_ZIPAPP)
     except KeyError:
       return False
-  return updater_script == patch_updater_module()
+  return updater_script == patch_updater_module() and APP_PATCH_MARKER.encode() in app_script
 
 
 def parse_inode(debugfs_output: str) -> int: