diff --git a/openpilot/common/prebuilt_manifest.py b/openpilot/common/prebuilt_manifest.py
new file mode 100644
index 0000000000..a95aff3fe7
--- /dev/null
+++ b/openpilot/common/prebuilt_manifest.py
@@ -0,0 +1,98 @@
+import hashlib
+import json
+import os
+from pathlib import Path
+import stat
+import subprocess
+import sys
+
+
+RECEIPT = 'prebuilt.json'
+RUNTIME_ROOTS = ('openpilot/system/ui/', 'openpilot/selfdrive/ui/', 'openpilot/starpilot/ui/',
+                 'openpilot/starpilot/software/', 'openpilot/starpilot/galaxy/')
+
+
+def protected(path):
+  if path in ('prebuilt', RECEIPT):
+    return False
+  if path.endswith('.py') and path.startswith(RUNTIME_ROOTS):
+    return False
+  if path.startswith('openpilot/starpilot/galaxy/') and path.endswith(('.html', '.css', '.js', '.svg', '.png', '.jpg', '.woff2')):
+    return False
+  return True
+
+
+def inventory_digest(entries):
+  inventory = sorted((path, mode, blob) for path, mode, blob in entries if protected(path))
+  return hashlib.sha256(json.dumps(inventory, separators=(',', ':'), ensure_ascii=True).encode()).hexdigest()
+
+
+def revision_digest(git, revision):
+  entries = []
+  for record in git('ls-tree', '-rz', '--full-tree', revision).split('\0'):
+    if record:
+      metadata, path = record.split('\t', 1)
+      mode, kind, blob = metadata.split()
+      if kind != 'blob':
+        raise ValueError('Prebuilt inventory contains non-file source')
+      entries.append((path, mode, blob))
+  return inventory_digest(entries)
+
+
+def valid_receipt(git, revision):
+  if git('ls-tree', revision, '--', RECEIPT).strip().split()[:1] != ['100644']:
+    return False
+  try:
+    receipt = json.loads(git('show', f'{revision}:{RECEIPT}'))
+    return (type(receipt) is dict and type(receipt.get('schema_version')) is int and receipt['schema_version'] == 1 and
+            receipt.get('protected_inventory_sha256') == revision_digest(git, revision))
+  except (ValueError, TypeError, KeyError):
+    return False
+
+
+def write_receipt(repo):
+  repo = Path(repo).resolve()
+  def git(*args, input=None):
+    return subprocess.check_output(['git', '-c', 'core.hooksPath=/dev/null', '-C', str(repo), *args],
+                                   input=input, timeout=30).decode()
+  entries = []
+  regular = []
+  for record in git('ls-files', '--stage', '-z').split('\0'):
+    if not record:
+      continue
+    metadata, path = record.split('\t', 1)
+    indexed_mode, _, stage = metadata.split()
+    if stage != '0' or indexed_mode == '160000':
+      raise ValueError('Prebuilt source has unresolved or nested Git entries')
+    if not protected(path):
+      continue
+    file = repo / path
+    info = file.lstat()
+    if stat.S_ISLNK(info.st_mode):
+      mode = '120000'
+      blob = git('hash-object', '--stdin', input=os.fsencode(os.readlink(file))).strip()
+    elif stat.S_ISREG(info.st_mode):
+      mode = '100755' if info.st_mode & 0o111 else '100644'
+      regular.append((path, mode))
+      continue
+    else:
+      raise ValueError('Prebuilt source contains a non-regular file')
+    entries.append((path, mode, blob))
+  for offset in range(0, len(regular), 256):
+    batch = regular[offset:offset + 256]
+    blobs = git('hash-object', '--no-filters', '--', *(path for path, _ in batch)).splitlines()
+    if len(blobs) != len(batch):
+      raise ValueError('Prebuilt source hashing was incomplete')
+    entries.extend((path, mode, blob) for (path, mode), blob in zip(batch, blobs, strict=True))
+  receipt = dict(schema_version=1, protected_inventory_sha256=inventory_digest(entries))
+  temporary = repo / (RECEIPT + '.tmp')
+  try:
+    temporary.write_text(json.dumps(receipt, sort_keys=True) + '\n')
+    os.replace(temporary, repo / RECEIPT)
+  finally:
+    temporary.unlink(missing_ok=True)
+  return receipt
+
+
+if __name__ == '__main__':
+  write_receipt(sys.argv[1])
diff --git a/openpilot/starpilot/galaxy/software_operations.py b/openpilot/starpilot/galaxy/software_operations.py
index 307130fd57..64f01fe4da 100644
--- a/openpilot/starpilot/galaxy/software_operations.py
+++ b/openpilot/starpilot/galaxy/software_operations.py
@@ -96,8 +96,8 @@ class UpdaterProcess:
       except (SoftwareOperationError, UpdaterControlError, OSError, RuntimeError, ValueError):
         return False
 
-  def send(self, action: str) -> None:
-    if action not in ("check", "download"):
+  def send(self, action: str, *, branch=None, commit=None) -> None:
+    if action not in ("check", "download", "fast"):
       raise SoftwareOperationError("Invalid updater command", 400)
     with self.lock:
       pid = self._manager_pid()
@@ -105,7 +105,10 @@ class UpdaterProcess:
       if self._manager_pid() != pid or self._proc_identity(pid) != start:
         raise SoftwareOperationError("Updater process changed", 503)
       try:
-        self.control.send(pid, start, action)
+        if action == "fast":
+          self.control.send(pid, start, action, branch=branch, commit=commit)
+        else:
+          self.control.send(pid, start, action)
       except (UpdaterControlError, OSError, RuntimeError, ValueError):
         raise SoftwareOperationError("Updater control is unavailable", 503) from None
 
@@ -158,6 +161,7 @@ class SoftwareOperations:
     self.request: dict | None = None
     self._baseline: tuple | None = None
     self._started = 0.0
+    self._fast_commit = None
 
   def _param(self, key: str, limit: int = 256) -> str | None:
     try:
@@ -236,15 +240,25 @@ class SoftwareOperations:
     if request is None or request["state"] != "pending" or request["action"] == "install":
       return
     state = status["updater"]["state"]
-    if request["target"] is not None and status["updater"]["targetBranch"] != request["target"]:
+    if request["action"] != "fast" and request["target"] is not None and status["updater"]["targetBranch"] != request["target"]:
       request.update(state="failed", error="Updater target changed")
     elif state == "idle" and status["updater"]["failedCount"] is not None and self._baseline[2] is not None and \
          status["updater"]["failedCount"] > self._baseline[2]:
-      request.update(state="failed", error="Updater reported a failure")
+      error = "Updater reported a failure"
+      if request["action"] == "fast":
+        try:
+          error = self._param("LastUpdateException", 4096) or error
+        except SoftwareOperationError:
+          pass
+      request.update(state="failed", error=error)
     elif state == "idle" and status["updater"]["failedCount"] == 0 and \
          status["updater"]["lastSuccessAt"] is not None and \
          status["updater"]["lastSuccessAt"] != self._baseline[0]:
-      if request["action"] == "check" or status["updater"]["lastFetchAt"] != self._baseline[1]:
+      if request["action"] == "fast":
+        if status["updater"]["lastFetchAt"] != self._baseline[1]:
+          restarting = self._flag("DoReboot") is True or status["installed"]["commit"] != self._fast_commit
+          request.update(state="complete", error=None, outcome="restarting" if restarting else "up_to_date")
+      elif request["action"] == "check" or status["updater"]["lastFetchAt"] != self._baseline[1]:
         request.update(state="complete", error=None)
       elif self._ready(status, request["target"]):
         request.update(state="complete", error=None)
@@ -284,7 +298,7 @@ class SoftwareOperations:
         reason = "Updater is not running"
       return {
         "parked": parked, "availableBranches": branches, "selectedTarget": target,
-        "canCheck": usable, "canSelect": usable and bool(branches),
+        "canCheck": usable, "canFastUpdate": usable and self._valid_branch(status["installed"]["branch"]), "canSelect": usable and bool(branches),
         "canDownload": usable and selected, "canInstall": usable and selected and self._ready(status, target),
         "reason": reason, "request": dict(self.request) if self.request is not None else None,
         "automaticDownloads": automatic_downloads(self.params), "canConfigure": parked and not reboot,
@@ -334,7 +348,7 @@ class SoftwareOperations:
       return self.snapshot()
 
   def action(self, action: str, payload: object, *, authorized: Callable[[], bool]) -> dict:
-    if type(payload) is not dict or type(action) is not str or action not in ("check", "download", "select", "install", "preferences"):
+    if type(payload) is not dict or type(action) is not str or action not in ("check", "download", "select", "install", "preferences", "fast"):
       raise SoftwareOperationError("Invalid software action", 400)
     if payload.get("action") != action or any(type(key) is not str for key in payload):
       raise SoftwareOperationError("Invalid software action", 400)
@@ -357,10 +371,15 @@ class SoftwareOperations:
         raise SoftwareOperationError("Vehicle is not safely parked", 409)
       if view["reason"] is not None:
         raise SoftwareOperationError(view["reason"], 503 if view["reason"] == "Updater is not running" else 409)
-      if branch is not None and branch not in view["availableBranches"]:
+      if action != "fast" and branch is not None and branch not in view["availableBranches"]:
         raise SoftwareOperationError("Branch is not in the current updater list", 409)
-      if action != "check" and action != "select" and (branch != view["selectedTarget"] or not view["canDownload"]):
+      if action not in ("check", "select", "fast") and (branch != view["selectedTarget"] or not view["canDownload"]):
         raise SoftwareOperationError("Selected updater target changed", 409)
+      if action == "fast":
+        installed = self.status.snapshot()["installed"]
+        identity = self.git_identity(self.installed)
+        if not view["canFastUpdate"] or branch != installed["branch"] or identity is None or identity != (branch, installed["commit"]):
+          raise SoftwareOperationError("Installed branch changed; refresh before updating", 409)
       if action == "install" and not view["canInstall"]:
         raise SoftwareOperationError("Finalized update does not match selected branch", 409)
       if not authorized() or not self._parked() or self._flag("IsOnroad") is not False:
@@ -368,7 +387,8 @@ class SoftwareOperations:
       current = self.status.snapshot()
       if (current["updater"]["state"] != "idle" or self._flag("DisableUpdates") is not False or
           self._flag("DoReboot") is not False or not self.process.available() or
-          (branch is not None and branch not in self._branches())):
+          (action != "fast" and branch is not None and branch not in self._branches()) or
+          (action == "fast" and current["installed"]["branch"] != branch)):
         raise SoftwareOperationError("Updater state changed", 409)
       if action == "select":
         self.params.put("UpdaterTargetBranch", branch, block=True)
@@ -387,7 +407,15 @@ class SoftwareOperations:
                     status["updater"]["failedCount"])
         if not authorized() or not self._parked() or self._flag("IsOnroad") is not False:
           raise SoftwareOperationError("Session or parked state changed", 403)
-        self.process.send(action)
+        if action == "fast":
+          identity = self.git_identity(self.installed)
+          if identity is None or identity != (branch, status["installed"]["commit"]) or status["installed"]["branch"] != branch:
+            raise SoftwareOperationError("Installed branch changed; refresh before updating", 409)
+          self._fast_commit = status["installed"]["commit"]
+        if action == "fast":
+          self.process.send(action, branch=identity[0], commit=identity[1])
+        else:
+          self.process.send(action)
       self.request = {"id": secrets.token_hex(8), "action": action,
                       "target": branch if branch is not None else status["updater"]["targetBranch"],
                       "state": "pending", "error": None}
diff --git a/openpilot/starpilot/galaxy/tests/test_software_operations.py b/openpilot/starpilot/galaxy/tests/test_software_operations.py
index 04ca6f8327..0032dc762a 100644
--- a/openpilot/starpilot/galaxy/tests/test_software_operations.py
+++ b/openpilot/starpilot/galaxy/tests/test_software_operations.py
@@ -16,14 +16,17 @@ class FakeProcess:
   def __init__(self):
     self.running = True
     self.sent = []
+    self.fast_requests = []
 
   def available(self):
     return self.running
 
-  def send(self, sig):
+  def send(self, sig, **identity):
     if not self.running:
       raise SoftwareOperationError("Updater stopped", 503)
     self.sent.append(sig)
+    if sig == "fast":
+      self.fast_requests.append(identity)
 
   def close(self):
     pass
@@ -265,6 +268,46 @@ class SoftwareOperationsTest(unittest.TestCase):
     self.assertEqual(reader.call_count, 4)
 
 
+  def test_fast_current_branch_without_branch_list_or_selected_target(self):
+    self.params.remove("UpdaterAvailableBranches")
+    self.params.put("UpdaterTargetBranch", "release", block=True)
+    self.assertTrue(self.owner.snapshot()["canFastUpdate"])
+    result = self.act("fast", "main")
+    self.assertEqual(result["request"]["target"], "main")
+    self.assertEqual(self.process.sent, ["fast"])
+    self.assertEqual(self.process.fast_requests, [{"branch": "main", "commit": "a" * 40}])
+    self.assertEqual(self.params.get("UpdaterTargetBranch"), "release")
+    self.assertFalse(self.params.get_bool("DoReboot"))
+    self.params.put("LastUpdateTime", datetime(2026, 10, 3, 12), block=True)
+    self.params.put("UpdaterLastFetchTime", datetime(2026, 10, 3, 12), block=True)
+    result = self.owner.snapshot()["request"]
+    self.assertEqual(result["state"], "complete")
+    self.assertEqual(result["outcome"], "up_to_date")
+
+  def test_fast_rejects_other_or_stale_installed_branch(self):
+    self.denied("fast", 409, "release")
+    self.git[self.installed] = ("main", "b" * 40)
+    self.denied("fast", 409, "main")
+    self.git[self.installed] = ("release", "a" * 40)
+    self.denied("fast", 409, "main")
+    self.assertEqual(self.process.sent, [])
+    self.assertFalse(self.params.get_bool("DoReboot"))
+
+  def test_fast_keeps_existing_admission_and_observes_failure(self):
+    for key in ("DisableUpdates", "IsOnroad", "DoReboot"):
+      self.params.put_bool(key, True, block=True)
+      self.denied("fast", 409, "main")
+      self.params.put_bool(key, False, block=True)
+    self.authorized = False
+    self.denied("fast", 403, "main")
+    self.authorized = True
+    self.act("fast", "main")
+    self.denied("fast", 409, "main")
+    self.params.put("UpdateFailedCount", 1, block=True)
+    self.assertEqual(self.owner.snapshot()["request"]["state"], "failed")
+    self.assertEqual(self.process.sent, ["fast"])
+
+
 class UpdaterIdentityTest(unittest.TestCase):
   def test_fresh_manager_pid_and_same_proc_start_before_signal(self):
     with tempfile.TemporaryDirectory() as temporary:
diff --git a/openpilot/starpilot/galaxy/tests/test_software_status.mjs b/openpilot/starpilot/galaxy/tests/test_software_status.mjs
index 2aac50ecef..77f7c0e354 100644
--- a/openpilot/starpilot/galaxy/tests/test_software_status.mjs
+++ b/openpilot/starpilot/galaxy/tests/test_software_status.mjs
@@ -324,3 +324,40 @@ assert(validSoftwareSnapshot(snapshot({ operations: { ...operations, automaticDo
 assert(!validSoftwareSnapshot(snapshot({ operations: { ...operations, history: { ...history, installed: [{ hash: '--help' }] } } })))
 assert(!validSoftwareSnapshot(snapshot({ operations: { ...operations, automaticDownloads: 'true' } })))
 assert.doesNotMatch(SoftwarePage.template, /v-html/)
+
+const fast = fixture()
+fast.feed.start()
+await fast.reply(0, snapshot({ operations: { ...operations, availableBranches: [], selectedTarget: "beta", canFastUpdate: true } }))
+fast.feed.action("fast", "beta")
+assert.equal(fast.requests.length, 1)
+fast.feed.action("fast", installed.branch)
+assert.deepEqual(JSON.parse(fast.requests[1].options.body), { action: "fast", branch: installed.branch })
+await fast.reply(1, snapshot({ operations: { ...operations, canFastUpdate: false, request: request("fast", "pending", installed.branch) }, updater: { ...updater, state: "updating..." } }))
+fast.feed.action("fast", installed.branch)
+assert.equal(fast.requests.length, 2)
+fast.fire(1000)
+await fast.reply(2, snapshot({ operations: { ...operations, canFastUpdate: true, request: { ...request("fast", "complete", installed.branch), outcome: "up_to_date" } } }))
+assert.equal(fast.feed.installBaseline, null)
+assert.match(fast.feed.notice, /already up to date/)
+fast.feed.stop()
+
+const fastLost = fixture()
+fastLost.feed.start()
+await fastLost.reply(0, snapshot({ operations: { ...operations, canFastUpdate: true } }))
+fastLost.feed.action("fast", installed.branch)
+await fastLost.fail(1)
+assert.equal(fastLost.feed.uncertain, true)
+fastLost.feed.action("fast", installed.branch)
+assert.equal(fastLost.requests.length, 2)
+fastLost.fire(2000)
+await fastLost.reply(2, snapshot({ installed: { ...installed, commit: "b".repeat(40) }, operations: { ...operations, canFastUpdate: true } }))
+assert.equal(fastLost.feed.installBaseline, null)
+assert.equal(fastLost.feed.uncertain, false)
+assert.match(fastLost.feed.notice, /verified after reconnect/)
+fastLost.feed.stop()
+
+const fastPage = { actionDisabled: false, operations: { canFastUpdate: true, selectedTarget: "beta" }, data: { installed }, dialog: null }
+SoftwarePage.methods.askFastUpdate.call(fastPage)
+assert.deepEqual(fastPage.dialog, { action: "fast", branch: "Dom", title: "Fast Update", message: "Download latest version of Dom and restart?", label: "Fast Update" })
+assert.equal(validSoftwareSnapshot(snapshot({ operations: { ...operations, canFastUpdate: "yes" } })), false)
+assert.equal(validSoftwareSnapshot(snapshot({ operations: { ...operations, request: { ...request("fast"), outcome: "invented" } } })), false)
diff --git a/openpilot/starpilot/galaxy/web/js/software-status.js b/openpilot/starpilot/galaxy/web/js/software-status.js
index ad068c0f53..5be9923a55 100644
--- a/openpilot/starpilot/galaxy/web/js/software-status.js
+++ b/openpilot/starpilot/galaxy/web/js/software-status.js
@@ -1,11 +1,11 @@
 import { decodeLayoutBackup, encodeLayoutBackup, MAX_LAYOUT_BACKUP_BYTES } from "./layout-backup.js"
 
-const ACTIONS = new Set(["check", "download", "select", "install", "preferences"])
+const ACTIONS = new Set(["check", "download", "select", "install", "preferences", "fast"])
 const REQUEST_STATES = new Set(["pending", "complete", "failed"])
-const UPDATER_ACTIVE = new Set(["checking...", "downloading...", "finalizing update..."])
+const UPDATER_ACTIVE = new Set(["checking...", "downloading...", "finalizing update...", "updating..."])
 const PRIMARY_BRANCHES = ["StarPilot", "Dom"]
 const unavailableOperations = () => ({ parked: false, availableBranches: [], selectedTarget: null,
-  canCheck: false, canDownload: false, canSelect: false, canInstall: false,
+  canCheck: false, canFastUpdate: false, canDownload: false, canSelect: false, canInstall: false,
   reason: "Update controls are unavailable", request: null })
 
 export function validSoftwareSnapshot(data) {
@@ -22,12 +22,14 @@ export function validSoftwareSnapshot(data) {
     operations.availableBranches.length <= 256 && operations.availableBranches.every((branch) =>
       typeof branch === "string" && branch.length > 0 && branch.length <= 128) &&
     text(operations.selectedTarget) && text(operations.reason) &&
+    (operations.canFastUpdate === undefined || typeof operations.canFastUpdate === "boolean") &&
     (operations.automaticDownloads === undefined || flag(operations.automaticDownloads)) &&
     (operations.canConfigure === undefined || typeof operations.canConfigure === "boolean") &&
     (operations.history === undefined || validHistory(operations.history)) &&
     [operations.canCheck, operations.canDownload, operations.canSelect, operations.canInstall].every((value) => typeof value === "boolean") &&
     (request === null || !!request && typeof request.id === "string" && request.id.length <= 100 &&
-      ACTIONS.has(request.action) && text(request.target) && REQUEST_STATES.has(request.state) && text(request.error)))
+      ACTIONS.has(request.action) && text(request.target) && REQUEST_STATES.has(request.state) && text(request.error) &&
+      (request.outcome === undefined || ["up_to_date", "restarting"].includes(request.outcome))))
 }
 
 export function validHistory(value) {
@@ -147,7 +149,9 @@ export class SoftwareStatusFeed {
         this.uncertain = false
         this.uncertainAction = null
         this.actionPriorRequestId = null
-        if (body.action === "install") {
+        if (body.action === "fast") {
+          this.notice = `Updating ${body.branch}. Waiting for completion or reconnect.`
+        } else if (body.action === "install") {
           this.installBaseline = this.installBaseline || { commit: payload.installed.commit, branch: payload.installed.branch, target: body.branch }
           this.notice = "Restart requested. Waiting to reconnect and verify the installed build."
         } else this.notice = body.action === "select" ? `Target branch set to ${body.branch}. Check and download the update when ready.` :
@@ -166,6 +170,13 @@ export class SoftwareStatusFeed {
           this.uncertainAction = null
           this.actionPriorRequestId = null
         }
+        if (this.installBaseline?.action === "fast" && observed?.action === "fast" && observed.target === this.installBaseline.target &&
+            ["complete", "failed"].includes(observed.state)) {
+          if (observed.state === "failed" || observed.outcome === "up_to_date") {
+            this.installBaseline = null
+            this.notice = observed.state === "failed" ? "" : "Installed branch is already up to date. No restart needed."
+          } else this.notice = "Update installed. Waiting to reconnect and verify the installed build."
+        }
         if (this.installBaseline && payload.installed.branch === this.installBaseline.target &&
             (payload.installed.commit && payload.installed.commit !== this.installBaseline.commit ||
              payload.installed.branch !== this.installBaseline.branch)) {
@@ -186,7 +197,7 @@ export class SoftwareStatusFeed {
         if (body !== null) {
           this.uncertain = !error?.rejected
           this.uncertainAction = this.uncertain ? body : null
-          if (error?.rejected && body.action === "install") this.installBaseline = null
+          if (error?.rejected && ["install", "fast"].includes(body.action)) this.installBaseline = null
         }
         this.error = error?.message || "Software request failed. Refresh to try again."
         this.emit(this.data ? "ready" : this.attempted ? "unavailable" : "loading")
@@ -214,14 +225,16 @@ export class SoftwareStatusFeed {
 
   action(action, branch = null) {
     const operations = this.data?.operations
-    const capability = { check: "canCheck", download: "canDownload", select: "canSelect", install: "canInstall" }[action]
+    const capability = { check: "canCheck", download: "canDownload", select: "canSelect", install: "canInstall", fast: "canFastUpdate" }[action]
     if (!this.active || !capability || this.mutating || this.blocked || this.uncertain || !operations?.parked ||
         operations[capability] !== true || operations.request?.state === "pending") return null
     if (action === "select" && (branch === "other:" || !operations.availableBranches.includes(branch) || branch === operations.selectedTarget)) return null
     if (["download", "install"].includes(action) && (!branch || branch !== operations.selectedTarget)) return null
+    if (action === "fast" && (!branch || branch !== this.data.installed.branch)) return null
     this.actionPriorRequestId = operations.request?.id ?? null
     if (action === "install") this.installBaseline = { commit: this.data.installed.commit,
       branch: this.data.installed.branch, target: branch }
+    if (action === "fast") this.installBaseline = { commit: this.data.installed.commit, branch: this.data.installed.branch, target: branch, action }
     return this.run(action === "check" ? { action } : { action, branch })
   }
 }
@@ -345,6 +358,9 @@ export const SoftwarePage = {
     requestMessage(request) {
       if (!request) return ""
       if (request.state === "failed") return request.error || "Update request failed. Refresh and try again."
+      if (request.action === "fast") return request.state === "pending" ? `Updating ${request.target}…` :
+        request.outcome === "up_to_date" ? "Installed branch is already up to date. No restart needed." :
+        "Update installed. Waiting to reconnect and verify the installed build."
       if (request.action === "install") return "Restart requested. Waiting to reconnect and verify the installed build."
       if (request.state === "pending") return request.action === "check" ? "Checking for updates…" : "Downloading and preparing update…"
       return request.action === "check" ? "Update check finished." : request.action === "download" ? "Download finished." : "Target branch saved."
@@ -354,6 +370,12 @@ export const SoftwarePage = {
       this.dialog = { action: "select", branch: this.draftBranch, title: "Change target branch",
         message: `Set ${this.draftBranch} as the target branch? This only stages the choice. Check for updates and download separately.`, label: "Set target branch" }
     },
+    askFastUpdate() {
+      const branch = this.data?.installed?.branch
+      if (this.actionDisabled || this.operations?.canFastUpdate !== true || !branch) return
+      this.dialog = { action: "fast", branch, title: "Fast Update",
+        message: `Download latest version of ${branch} and restart?`, label: "Fast Update" }
+    },
     askInstall() {
       if (this.actionDisabled || !this.operations?.canInstall || !this.operations.selectedTarget) return
       this.dialog = { action: "install", branch: this.operations.selectedTarget, title: "Restart and install update",
@@ -412,7 +434,8 @@ export const SoftwarePage = {
             <p v-else-if="data.updater.state">{{ data.updater.state }}</p>
             <p v-if="data.updater.targetChangeFound === true">An update was found for the target branch.</p>
             <p v-else-if="data.updater.targetChangeFound === false">No target change reported by the last check.</p>
-            <div class="gx-software-actions"><button type="button" class="gx-btn" :disabled="actionDisabled || !operations.canDownload || !operations.selectedTarget" @click="feed.action('download', operations.selectedTarget)">Download update</button>
+            <div class="gx-software-actions"><button type="button" class="gx-btn" :disabled="actionDisabled || operations.canFastUpdate !== true || !data.installed.branch" @click="askFastUpdate">Fast Update</button>
+              <button type="button" class="gx-btn" :disabled="actionDisabled || !operations.canDownload || !operations.selectedTarget" @click="feed.action('download', operations.selectedTarget)">Download update</button>
               <button type="button" class="gx-btn" :disabled="actionDisabled || !operations.canInstall || !operations.selectedTarget" @click="askInstall">Restart &amp; install</button></div>
             <dl><dt>Last checked</dt><dd>{{ reported(data.updater.lastSuccessAt) }}</dd><dt>Last download</dt><dd>{{ reported(data.updater.lastFetchAt) }}</dd></dl></section>
           <section v-if="operations.automaticDownloads !== undefined" class="gx-card gx-software-card">
diff --git a/openpilot/starpilot/software/fast_update.py b/openpilot/starpilot/software/fast_update.py
new file mode 100644
index 0000000000..7aaad4a7d6
--- /dev/null
+++ b/openpilot/starpilot/software/fast_update.py
@@ -0,0 +1,83 @@
+import os
+from pathlib import Path
+import re
+import subprocess
+
+from openpilot.common.vendor_manifest import validate_revision
+from openpilot.common.prebuilt_manifest import revision_digest, valid_receipt
+
+
+class FastUpdateError(RuntimeError):
+  pass
+
+
+def run(command, cwd):
+  environment = dict(os.environ, GIT_LFS_SKIP_SMUDGE='1', GIT_TERMINAL_PROMPT='0')
+  return subprocess.check_output(command, cwd=cwd, env=environment, stderr=subprocess.STDOUT,
+                                 timeout=120 if "fetch" in command or "reset" in command else 30).decode()
+
+
+def fast_update(repo, branch, *, params, parked, expected_commit, current_os=None, invalidate=None, run=run):
+  repo = Path(repo)
+
+  def git(*arguments):
+    return run(['git', '-c', 'gc.auto=0', '-c', 'maintenance.auto=false', '-c', 'core.hooksPath=/dev/null', '-c', 'submodule.recurse=false', '-c', 'filter.lfs.required=false',
+                '-c', 'filter.lfs.smudge=', '-c', 'filter.lfs.process=', *arguments], cwd=str(repo))
+
+  def admitted():
+    if not parked():
+      raise FastUpdateError('Fast Update requires fresh parked state')
+    if git('symbolic-ref', '--short', 'HEAD').strip() != branch:
+      raise FastUpdateError('Fast Update only updates the current branch')
+    if git('status', '--porcelain', '--untracked-files=no').strip():
+      raise FastUpdateError('Tracked source has local changes')
+
+  git('check-ref-format', '--branch', branch)
+  admitted()
+  previous = git('rev-parse', 'HEAD^{commit}').strip()
+  if not isinstance(expected_commit, str) or not re.fullmatch(r'[0-9a-f]{40}', expected_commit) or previous != expected_commit:
+    raise FastUpdateError('Approved source revision changed; refresh and try again')
+  git('fetch', '--depth=1', '--no-tags', '--no-recurse-submodules', 'origin', f'refs/heads/{branch}')
+  target = git('rev-parse', 'FETCH_HEAD^{commit}').strip()
+  validate_revision(repo, target)
+  launch = git('show', f'{target}:launch_env.sh')
+  versions = re.findall(r'^\s*export\s+AGNOS_VERSION=["\']([^"\'\n]+)["\']\s*$', launch, re.MULTILINE)
+  if len(versions) != 1 or not current_os or versions[0] != current_os:
+    raise FastUpdateError('Update requires a different or unverified operating system')
+  if target == previous:
+    return 'up-to-date'
+  for revision in (previous, target):
+    if git('ls-tree', revision, '--', 'prebuilt').strip().split()[:1] != ['100644']:
+      raise FastUpdateError('Fast Update requires prebuilt releases; use a full validated update')
+  if not valid_receipt(git, target) and revision_digest(git, previous) != revision_digest(git, target):
+    raise FastUpdateError('Native build inputs or artifacts changed without a matching build receipt; use a full validated update')
+  tracked = set(git('ls-tree', '-rz', '--name-only', target).split('\0')) - {''}
+  untracked = set(git('ls-files', '--others', '-z').split('\0')) - {''}
+  directories = {str(parent) for name in tracked for parent in Path(name).parents if str(parent) != '.'}
+  for name in untracked:
+    if name in tracked or name in directories or any(str(parent) in tracked for parent in Path(name).parents):
+      raise FastUpdateError('Update would overwrite untracked data')
+  admitted()
+  if git('rev-parse', 'HEAD^{commit}').strip() != previous:
+    raise FastUpdateError('Source changed during download')
+  if invalidate is None:
+    raise FastUpdateError('Update staging invalidation is unavailable')
+  git('update-ref', 'refs/starpilot/previous', previous)
+  invalidate()
+  admitted()
+  if git('rev-parse', 'HEAD^{commit}').strip() != previous:
+    raise FastUpdateError('Source changed before installation')
+  try:
+    git('reset', '--hard', '--no-recurse-submodules', target)
+    if git('rev-parse', 'HEAD^{commit}').strip() != target:
+      raise FastUpdateError('Applied source revision does not match download')
+    validate_revision(repo, 'HEAD')
+    if not parked():
+      raise FastUpdateError('Parked state changed before restart')
+    params.put_bool('DoReboot', True, block=True)
+  except Exception:
+    git('reset', '--hard', '--no-recurse-submodules', previous)
+    if git('rev-parse', 'HEAD^{commit}').strip() != previous:
+      raise FastUpdateError('Source rollback failed')
+    raise
+  return 'reboot-requested'
diff --git a/openpilot/starpilot/software/tests/test_fast_update.py b/openpilot/starpilot/software/tests/test_fast_update.py
new file mode 100644
index 0000000000..7139b00f18
--- /dev/null
+++ b/openpilot/starpilot/software/tests/test_fast_update.py
@@ -0,0 +1,279 @@
+import importlib.util
+import json
+from pathlib import Path
+import subprocess
+import sys
+import tempfile
+import unittest
+from unittest.mock import patch
+
+
+ROOT = Path(__file__).resolve().parents[3]
+
+
+def load(name, path):
+  spec = importlib.util.spec_from_file_location(name, path)
+  module = importlib.util.module_from_spec(spec)
+  sys.modules[name] = module
+  spec.loader.exec_module(module)
+  return module
+
+
+vendor = load('openpilot.common.vendor_manifest', ROOT / 'common/vendor_manifest.py')
+prebuilt = load('openpilot.common.prebuilt_manifest', ROOT / 'common/prebuilt_manifest.py')
+owner = load('fast_update_owner', ROOT / 'starpilot/software/fast_update.py')
+
+
+class Params:
+  def __init__(self):
+    self.calls = []
+
+  def put_bool(self, *args, **kwargs):
+    self.calls.append((args, kwargs))
+
+
+class TestFastUpdate(unittest.TestCase):
+  def git(self, repo, *args):
+    return subprocess.check_output(['git', '-C', str(repo), *args], stderr=subprocess.STDOUT).decode().strip()
+
+  def setUp(self):
+    self.temp = tempfile.TemporaryDirectory()
+    self.addCleanup(self.temp.cleanup)
+    base = Path(self.temp.name)
+    self.remote, self.repo = base / 'remote', base / 'repo'
+    self.remote.mkdir()
+    self.git(self.remote, 'init', '-b', 'Dom')
+    self.git(self.remote, 'config', 'user.name', 'Test')
+    self.git(self.remote, 'config', 'user.email', 'test@example.invalid')
+    dependencies = []
+    for name in sorted(vendor.DEPENDENCIES):
+      (self.remote / name).mkdir()
+      (self.remote / name / 'source').write_text('vendored')
+      dependencies.append(dict(path=name, commit='1' * 40, tree='2' * 40, url='https://example.invalid/source', exclude=[]))
+    manifest = dict(schema_version=1, upstream=dict(commit='3' * 40, url='https://example.invalid/upstream'), dependencies=dependencies)
+    (self.remote / 'upstream-sync.json').write_text(json.dumps(manifest))
+    (self.remote / 'launch_env.sh').write_text('export AGNOS_VERSION="19.8.1"\n')
+    (self.remote / 'prebuilt').write_text('')
+    (self.remote / 'openpilot/starpilot/ui').mkdir(parents=True)
+    (self.remote / 'openpilot/starpilot/ui/source.py').write_text('old')
+    self.git(self.remote, 'add', '.')
+    self.git(self.remote, 'commit', '-m', 'initial')
+    self.git(base, 'clone', '--no-local', str(self.remote), str(self.repo))
+    self.previous = self.git(self.repo, 'rev-parse', 'HEAD')
+    (self.remote / 'openpilot/starpilot/ui/source.py').write_text('new')
+    self.git(self.remote, 'commit', '-am', 'update')
+    self.target = self.git(self.remote, 'rev-parse', 'HEAD')
+    self.params = Params()
+    self.invalidations = []
+
+  def update(self, **kwargs):
+    arguments = dict(params=self.params, parked=lambda: True, expected_commit=self.git(self.repo, 'rev-parse', 'HEAD'), current_os='19.8.1',
+                     invalidate=lambda: self.invalidations.append(True))
+    arguments.update(kwargs)
+    return owner.fast_update(self.repo, 'Dom', **arguments)
+
+  def test_applies_exact_revision_and_retains_untracked_models(self):
+    (self.repo / 'models').mkdir()
+    (self.repo / 'models' / 'download').write_bytes(b'model')
+    commands = []
+    def traced(command, cwd):
+      commands.append(command)
+      return owner.run(command, cwd)
+    self.assertEqual(self.update(run=traced), 'reboot-requested')
+    fetch = next(command for command in commands if 'fetch' in command)
+    self.assertIn('gc.auto=0', fetch)
+    self.assertIn('maintenance.auto=false', fetch)
+    self.assertIn('--depth=1', fetch)
+    self.assertIn('--no-tags', fetch)
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.target)
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'refs/starpilot/previous'), self.previous)
+    self.assertEqual((self.repo / 'models' / 'download').read_bytes(), b'model')
+    self.assertEqual(self.params.calls, [(('DoReboot', True), dict(block=True))])
+    self.assertEqual(self.update(), 'up-to-date')
+    self.assertEqual(len(self.invalidations), 1)
+
+  def test_expected_commit_changed_rejected_before_fetch(self):
+    commands = []
+    def traced(command, cwd):
+      commands.append(command)
+      return owner.run(command, cwd)
+    with self.assertRaises(owner.FastUpdateError):
+      self.update(expected_commit='1' * 40, run=traced)
+    self.assertFalse(any('fetch' in command for command in commands))
+
+  def test_source_only_ui_update_admitted(self):
+    folder = self.remote / 'openpilot/starpilot/ui'
+    folder.mkdir(parents=True, exist_ok=True)
+    (folder / 'runtime_app.py').write_text('value = 1')
+    self.git(self.remote, 'add', '.')
+    self.git(self.remote, 'commit', '-m', 'UI update')
+    self.assertEqual(self.update(), 'reboot-requested')
+
+  def test_native_source_change_rejected_without_artifact_proof(self):
+    (self.remote / 'native.cc').write_text('int main() {}')
+    self.git(self.remote, 'add', '.')
+    self.git(self.remote, 'commit', '-m', 'native update')
+    with self.assertRaisesRegex(owner.FastUpdateError, 'full validated update'):
+      self.update()
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.invalidations)
+
+  def receipt_commit(self):
+    prebuilt.write_receipt(self.remote)
+    self.git(self.remote, 'add', 'prebuilt.json')
+    self.git(self.remote, 'commit', '-m', 'validated receipt')
+
+  def test_matching_receipt_admits_native_source_and_artifacts(self):
+    (self.remote / 'native.cc').write_text('int source;')
+    (self.remote / 'native.so').write_bytes(b'compiled artifact fixture')
+    self.git(self.remote, 'add', '.')
+    self.receipt_commit()
+    self.assertEqual(self.update(), 'reboot-requested')
+
+  def test_receipt_stale_source_rejected(self):
+    (self.remote / 'native.cc').write_text('int source;')
+    self.git(self.remote, 'add', '.')
+    self.receipt_commit()
+    (self.remote / 'native.cc').write_text('int changed;')
+    self.git(self.remote, 'commit', '-am', 'stale source')
+    with self.assertRaisesRegex(owner.FastUpdateError, 'matching build receipt'):
+      self.update()
+    self.assertFalse(self.invalidations)
+
+  def test_receipt_stale_artifact_rejected(self):
+    (self.remote / 'native.so').write_bytes(b'artifact')
+    self.git(self.remote, 'add', '.')
+    self.receipt_commit()
+    (self.remote / 'native.so').write_bytes(b'changed artifact')
+    self.git(self.remote, 'commit', '-am', 'stale artifact')
+    with self.assertRaisesRegex(owner.FastUpdateError, 'matching build receipt'):
+      self.update()
+    self.assertFalse(self.invalidations)
+
+  def test_receipt_working_content_and_modes_match_committed_tree(self):
+    (self.remote / 'native.cc').write_text('int unstaged;')
+    self.git(self.remote, 'add', '.')
+    (self.remote / 'native.cc').write_text('int working;')
+    (self.remote / 'native.cc').chmod(0o755)
+    (self.remote / 'native-link').symlink_to('native.cc')
+    self.git(self.remote, 'add', 'native-link')
+    prebuilt.write_receipt(self.remote)
+    self.git(self.remote, 'add', '.')
+    self.git(self.remote, 'commit', '-m', 'receipt content and modes')
+    git = lambda *args: subprocess.check_output(['git', '-C', str(self.remote), *args]).decode()
+    self.assertTrue(prebuilt.valid_receipt(git, 'HEAD'))
+
+  def test_missing_prebuilt_rejected_without_removing_local_marker(self):
+    self.git(self.remote, 'rm', 'prebuilt')
+    self.git(self.remote, 'commit', '-m', 'nonprebuilt')
+    with self.assertRaisesRegex(owner.FastUpdateError, 'prebuilt'):
+      self.update()
+    self.assertTrue((self.repo / 'prebuilt').exists())
+
+  def test_wrong_os_rejected_before_mutation(self):
+    with self.assertRaises(owner.FastUpdateError):
+      self.update(current_os='19.8.2')
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.invalidations)
+    self.assertFalse(self.params.calls)
+
+  def test_dirty_tracked_source_rejected(self):
+    (self.repo / 'openpilot/starpilot/ui/source.py').write_text('local repair')
+    with self.assertRaises(owner.FastUpdateError):
+      self.update()
+    self.assertEqual((self.repo / 'openpilot/starpilot/ui/source.py').read_text(), 'local repair')
+
+  def test_staged_source_rejected(self):
+    (self.repo / 'openpilot/starpilot/ui/source.py').write_text('staged repair')
+    self.git(self.repo, 'add', 'openpilot/starpilot/ui/source.py')
+    with self.assertRaises(owner.FastUpdateError):
+      self.update()
+    self.assertEqual((self.repo / 'openpilot/starpilot/ui/source.py').read_text(), 'staged repair')
+    self.assertFalse(self.invalidations)
+
+  def test_reboot_write_failure_rolls_back(self):
+    def failing(*args, **kwargs):
+      raise RuntimeError('params write failed')
+    self.params.put_bool = failing
+    with self.assertRaisesRegex(RuntimeError, 'params write failed'):
+      self.update()
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+
+  def test_fetch_failure_does_not_mutate(self):
+    def failing(command, cwd):
+      if 'fetch' in command:
+        raise RuntimeError('fetch failed')
+      return owner.run(command, cwd)
+    with self.assertRaisesRegex(RuntimeError, 'fetch failed'):
+      self.update(run=failing)
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.invalidations)
+
+  def test_apply_failure_rolls_back(self):
+    failed = False
+    def failing(command, cwd):
+      nonlocal failed
+      if 'reset' in command and command[-1] == self.target and not failed:
+        failed = True
+        owner.run(command, cwd)
+        raise RuntimeError('apply failed after reset')
+      return owner.run(command, cwd)
+    with self.assertRaisesRegex(RuntimeError, 'apply failed'):
+      self.update(run=failing)
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertEqual((self.repo / 'openpilot/starpilot/ui/source.py').read_text(), 'old')
+    self.assertFalse(self.params.calls)
+
+  def test_lost_parked_before_reboot_rolls_back(self):
+    states = iter([True, True, True, False])
+    with self.assertRaises(owner.FastUpdateError):
+      self.update(parked=lambda: next(states))
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.params.calls)
+
+  def test_lost_parked_before_source_mutation(self):
+    states = iter([True, False])
+    with self.assertRaises(owner.FastUpdateError):
+      self.update(parked=lambda: next(states))
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.invalidations)
+
+  def test_invalid_vendor_target_rejected_before_checkout(self):
+    (self.remote / 'upstream-sync.json').write_text('{}')
+    self.git(self.remote, 'commit', '-am', 'invalid')
+    with self.assertRaises(ValueError):
+      self.update()
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.invalidations)
+
+  def test_other_branch_rejected(self):
+    self.git(self.repo, 'checkout', '-b', 'Other')
+    with self.assertRaises(owner.FastUpdateError):
+      self.update()
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+
+  def test_untracked_collision_rejected(self):
+    (self.repo / 'new-model').write_bytes(b'model')
+    (self.remote / 'new-model').write_text('tracked update')
+    self.git(self.remote, 'add', 'new-model')
+    self.receipt_commit()
+    with self.assertRaisesRegex(owner.FastUpdateError, 'overwrite untracked data'):
+      self.update()
+    self.assertEqual((self.repo / 'new-model').read_bytes(), b'model')
+    self.assertFalse(self.invalidations)
+
+  def test_post_apply_validation_failure_rolls_back(self):
+    original = owner.validate_revision
+    def validate(repo, revision):
+      if revision == 'HEAD':
+        raise ValueError('post-check failed')
+      return original(repo, revision)
+    with patch.object(owner, 'validate_revision', validate):
+      with self.assertRaisesRegex(ValueError, 'post-check failed'):
+        self.update()
+    self.assertEqual(self.git(self.repo, 'rev-parse', 'HEAD'), self.previous)
+    self.assertFalse(self.params.calls)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/openpilot/starpilot/software/tests/test_update_control.py b/openpilot/starpilot/software/tests/test_update_control.py
index a51bf04e57..acc86d99c2 100644
--- a/openpilot/starpilot/software/tests/test_update_control.py
+++ b/openpilot/starpilot/software/tests/test_update_control.py
@@ -14,6 +14,47 @@ class UpdaterControlTests(unittest.TestCase):
     with self.assertRaises(update_control.UpdaterControlError):
       update_control.send(0, 0, 'install')
 
+  def test_fast_wire_pins_branch_and_commit_without_changing_legacy_commands(self):
+    commit = 'a' * 40
+    with mock.patch.object(update_control, '_exchange') as exchange:
+      update_control.send(123, 456, 'fast', branch='SecretGoodStarPilot', commit=commit)
+      exchange.assert_called_once_with(123, 456, b'fast SecretGoodStarPilot ' + commit.encode())
+    self.assertEqual(update_control._parse(b'fast SecretGoodStarPilot ' + commit.encode() + b'\n'),
+                     ('fast', 'SecretGoodStarPilot', commit))
+    for action in ('check', 'download'):
+      self.assertEqual(update_control._command(action), action.encode())
+      self.assertEqual(update_control._parse(action.encode() + b'\n'), (action, None, None))
+    self.assertLessEqual(len(update_control._command('fast', 'x' * 128, commit)) + 1, update_control.MAX_COMMAND)
+    for raw in (b'fast\n', b'fast Dom bad\n', b'fast Dom ' + commit.encode(),
+                b'fast Dom ' + commit.encode() + b' extra\n', b'fast Dom\ncheck ' + commit.encode() + b'\n'):
+      with self.subTest(raw=raw), self.assertRaises(update_control.UpdaterControlError):
+        update_control._parse(raw)
+    for branch, revision in ((None, commit), ('Dom', None), ('Dom\ncheck', commit), ('x' * 129, commit), ('Dom', 'A' * 40)):
+      with self.subTest(branch=branch), self.assertRaises(update_control.UpdaterControlError):
+        update_control.send(123, 456, 'fast', branch=branch, commit=revision)
+    with self.assertRaises(update_control.UpdaterControlError):
+      update_control.send(123, 456, 'check', branch='Dom', commit=commit)
+
+  def test_server_delivers_fast_identity_and_legacy_callback_shape(self):
+    for raw, expected in ((b'fast Dom ' + b'a' * 40 + b'\n', mock.call('fast', branch='Dom', commit='a' * 40)),
+                          (b'check\n', mock.call('check')), (b'download\n', mock.call('download'))):
+      with self.subTest(raw=raw):
+        client, connection = socket.socketpair()
+        try:
+          client.settimeout(1)
+          client.sendall(raw)
+          callback = mock.Mock()
+          listener = mock.Mock()
+          listener.accept.side_effect = [(connection, None), OSError()]
+          server = update_control.UpdaterControlServer(callback)
+          with mock.patch.object(update_control, '_peer', return_value=(os.getpid(), os.geteuid())):
+            server._run(listener)
+          self.assertEqual(client.recv(16), b'ok\n')
+          self.assertEqual(callback.call_args, expected)
+        finally:
+          client.close()
+          connection.close()
+
   @unittest.skipUnless(sys.platform.startswith('linux') and hasattr(socket, 'SO_PEERCRED'), 'Linux peer credentials required')
   def test_same_process_control_and_stale_identity(self):
     actions = []
diff --git a/openpilot/starpilot/software/update_control.py b/openpilot/starpilot/software/update_control.py
index c0d6838201..4304f3fb00 100644
--- a/openpilot/starpilot/software/update_control.py
+++ b/openpilot/starpilot/software/update_control.py
@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 import os
+import re
 import socket
 import struct
 import threading
@@ -11,7 +12,9 @@ from pathlib import Path
 
 
 TIMEOUT = 0.5
-MAX_COMMAND = 16
+MAX_COMMAND = 256
+_BRANCH = re.compile(r"[A-Za-z0-9_][A-Za-z0-9._/+@-]{0,127}\Z")
+_COMMIT = re.compile(r"[0-9a-f]{40}\Z")
 _CREDENTIALS = struct.Struct('3i')
 
 
@@ -78,14 +81,32 @@ def available(pid: int, start: int) -> bool:
     return False
 
 
-def send(pid: int, start: int, action: str) -> None:
-  if action not in ('check', 'download'):
-    raise UpdaterControlError('Invalid updater control action')
-  _exchange(pid, start, action.encode('ascii'))
+def _command(action: str, branch=None, commit=None) -> bytes:
+  if action in ('check', 'download') and branch is None and commit is None:
+    return action.encode('ascii')
+  if action == 'fast' and type(branch) is str and type(commit) is str and _BRANCH.fullmatch(branch) and _COMMIT.fullmatch(commit):
+    return f'fast {branch} {commit}'.encode('ascii')
+  raise UpdaterControlError('Invalid updater control action')
+
+
+def _parse(command: bytes):
+  if command in (b'status\n', b'check\n', b'download\n'):
+    return command[:-1].decode('ascii'), None, None
+  try:
+    action, branch, commit = command[:-1].decode('ascii').split(' ')
+  except (UnicodeError, ValueError):
+    raise UpdaterControlError('Invalid updater control message') from None
+  if not command.endswith(b'\n') or action != 'fast' or _command(action, branch, commit) + b'\n' != command:
+    raise UpdaterControlError('Invalid updater control message')
+  return action, branch, commit
+
+
+def send(pid: int, start: int, action: str, *, branch=None, commit=None) -> None:
+  _exchange(pid, start, _command(action, branch, commit))
 
 
 class UpdaterControlServer:
-  def __init__(self, request: Callable[[str], None]):
+  def __init__(self, request: Callable[..., None]):
     self.request = request
     self.socket: socket.socket | None = None
     self.thread: threading.Thread | None = None
@@ -123,13 +144,21 @@ class UpdaterControlServer:
         try:
           _, uid = _peer(connection)
           command = _line(connection)
-          if uid != os.geteuid() or command not in (b'status\n', b'check\n', b'download\n'):
+          if uid != os.geteuid():
             connection.sendall(b'error\n')
           else:
-            if command != b'status\n':
-              self.request(command[:-1].decode('ascii'))
+            action, branch, commit = _parse(command)
+            if action == 'fast':
+              self.request(action, branch=branch, commit=commit)
+            elif action != 'status':
+              self.request(action)
             connection.sendall(b'ok\n')
-        except (OSError, RuntimeError, ValueError):
+        except (RuntimeError, ValueError):
+          try:
+            connection.sendall(b'error\n')
+          except OSError:
+            pass
+        except OSError:
           pass
 
   def close(self) -> None:
diff --git a/openpilot/system/updated/tests/test_fast_request.py b/openpilot/system/updated/tests/test_fast_request.py
new file mode 100644
index 0000000000..825d1269f5
--- /dev/null
+++ b/openpilot/system/updated/tests/test_fast_request.py
@@ -0,0 +1,152 @@
+from pathlib import Path
+import tempfile
+import threading
+import sys
+from types import ModuleType
+import unittest
+from unittest.mock import Mock, patch
+
+from openpilot.system.updated.tests.test_vendored_update import load_updater
+
+
+class StopLoop(Exception):
+  pass
+
+
+class TestFastRequest(unittest.TestCase):
+  def setUp(self):
+    self.updated = load_updater()
+    self.directory = tempfile.TemporaryDirectory()
+    self.addCleanup(self.directory.cleanup)
+    root = Path(self.directory.name)
+    self.updated.LOCK_FILE = str(root / 'lock')
+    self.updated.STAGING_ROOT = str(root / 'staging')
+    self.updated.OVERLAY_INIT = root / 'overlay'
+    self.params = Mock()
+    self.values = {'InstallDate': '2026-10-03', 'UpdateFailedCount': 2}
+    self.writes = []
+    self.params.get.side_effect = lambda key, **kwargs: self.values.get(key)
+    self.params.get_bool.side_effect = lambda key: bool(self.values.get(key, False))
+    def put(key, value, **kwargs):
+      self.writes.append((key, value))
+      self.values[key] = value
+    self.params.put.side_effect = put
+    self.params.put_bool.side_effect = put
+    self.params.remove.side_effect = lambda key: self.values.pop(key, None)
+    self.updated.Params = Mock(return_value=self.params)
+    self.helper = self.updated.WaitTimeHelper.__new__(self.updated.WaitTimeHelper)
+    self.helper.ready_event = threading.Event()
+    self.helper.request_lock = threading.RLock()
+    self.helper.request_generation = 0
+    self.helper.fast_target = None
+    self.helper.user_request = self.updated.UserRequest.NONE
+    self.helper._control_request('fast', branch='SecretGoodStarPilot', commit='a' * 40)
+    self.helper.sleep = Mock(side_effect=StopLoop)
+    self.updated.WaitTimeHelper = Mock(return_value=self.helper)
+    self.updater = Mock()
+    self.updater.fast_update.return_value = 'up-to-date'
+    self.updated.Updater = Mock(return_value=self.updater)
+    self.updated.init_overlay = Mock()
+    self.updated.set_consistent_flag = Mock()
+
+  def run_cycle(self):
+    with self.assertRaises(StopLoop):
+      self.updated.main()
+    self.updated.init_overlay.assert_not_called()
+    self.updater.check_for_update.assert_not_called()
+    self.updater.fetch_update.assert_not_called()
+    self.updater.set_params.assert_not_called()
+    self.updated.system_time_valid.assert_not_called()
+    self.updater.fast_update.assert_called_once_with('SecretGoodStarPilot', 'a' * 40)
+
+  def test_fast_request_skips_staging_and_startup_delay(self):
+    self.run_cycle()
+    self.assertEqual(self.values['UpdaterState'], 'idle')
+    self.assertEqual(self.values['UpdateFailedCount'], 0)
+    self.assertIn('UpdaterLastFetchTime', self.values)
+    self.assertIn('LastUpdateTime', self.values)
+    self.assertNotIn('DoReboot', self.values)
+    self.assertLess(self.writes.index(('UpdateFailedCount', 0)), len(self.writes) - 1)
+    self.assertEqual(self.writes[-1], ('UpdaterState', 'idle'))
+
+  def test_fast_failure_reports_error_without_reboot(self):
+    self.updater.fast_update.side_effect = RuntimeError('Tracked source has local changes')
+    self.run_cycle()
+    self.assertEqual(self.values['UpdaterState'], 'idle')
+    self.assertEqual(self.values['UpdateFailedCount'], 3)
+    self.assertEqual(self.values['LastUpdateException'], 'Tracked source has local changes')
+    self.assertNotIn('DoReboot', self.values)
+    self.assertNotIn('LastUpdateTime', self.values)
+
+  def test_long_failure_remains_readable_by_galaxy(self):
+    self.updater.fast_update.side_effect = RuntimeError('download failed: ' + 'é' * 5000)
+    self.run_cycle()
+    self.assertLessEqual(len(self.values['LastUpdateException'].encode('utf-8')), 4096)
+    self.assertTrue(self.values['LastUpdateException'].startswith('download failed: '))
+    self.assertEqual(self.values['UpdaterState'], 'idle')
+
+  def test_success_waits_for_manager_restart(self):
+    def apply(branch, commit):
+      self.params.put_bool('DoReboot', True, block=True)
+      return 'reboot-requested'
+    self.updater.fast_update.side_effect = apply
+    self.run_cycle()
+    self.assertEqual(self.values['UpdaterState'], 'updating...')
+    self.assertTrue(self.values['DoReboot'])
+
+  def test_new_request_is_not_lost_when_previous_work_finishes(self):
+    _, generation, target = self.helper.current_request()
+    self.assertEqual(target, ('SecretGoodStarPilot', 'a' * 40))
+    self.helper._control_request('check')
+    self.assertFalse(self.helper.finish_request(generation))
+    self.assertTrue(self.helper.ready_event.is_set())
+    request, generation, target = self.helper.current_request()
+    self.assertIsNone(target)
+    self.assertEqual(request, self.updated.UserRequest.CHECK)
+    self.assertTrue(self.helper.finish_request(generation))
+    self.assertEqual(self.helper.user_request, self.updated.UserRequest.NONE)
+    self.assertFalse(self.helper.ready_event.is_set())
+
+
+class TestFastAdapter(unittest.TestCase):
+  def test_source_admission_and_overlay_invalidation_are_owned_by_updater(self):
+    updated = load_updater()
+    with tempfile.TemporaryDirectory() as directory:
+      root = Path(directory)
+      updated.FINALIZED = str(root / 'finalized')
+      Path(updated.FINALIZED).mkdir()
+      marker = Path(updated.FINALIZED, '.overlay_consistent')
+      marker.touch()
+      updated.OVERLAY_INIT = root / '.overlay_init'
+      updated.OVERLAY_INIT.touch()
+      updated.BASEDIR = str(root)
+      updated.dismount_overlay = Mock()
+      updated.HARDWARE.get_os_version.return_value = '19.8.1'
+      updater = updated.Updater()
+      updater.params = Mock()
+      updater.params.get_bool.side_effect = lambda key: key == 'IsOffroad'
+      source = Mock()
+      source.allowed.return_value = True
+      source.effective.return_value = False
+      physical = ModuleType('openpilot.starpilot.drive_state.evidence')
+      physical.PhysicalSource = Mock(return_value=source)
+      owner = ModuleType('openpilot.starpilot.software.fast_update')
+      def install(repo, branch, **options):
+        self.assertEqual((repo, branch, options['expected_commit'], options['current_os']),
+                         (root, 'SecretGoodStarPilot', 'b' * 40, '19.8.1'))
+        self.assertTrue(options['parked']())
+        self.assertTrue(marker.exists())
+        options['invalidate']()
+        self.assertFalse(marker.exists())
+        self.assertFalse(updated.OVERLAY_INIT.exists())
+        updated.dismount_overlay.assert_called_once()
+        return 'reboot-requested'
+      owner.fast_update = install
+      with patch.dict(sys.modules, {physical.__name__: physical, owner.__name__: owner}):
+        self.assertEqual(updater.fast_update('SecretGoodStarPilot', 'b' * 40), 'reboot-requested')
+      source.close.assert_called_once()
+      updater.params.put_bool.assert_called_once_with('UpdateAvailable', False, block=True)
+
+
+if __name__ == '__main__':
+  unittest.main()
diff --git a/openpilot/system/updated/tests/test_unpublished_branch.py b/openpilot/system/updated/tests/test_unpublished_branch.py
index 56917d1692..e9a73d0550 100644
--- a/openpilot/system/updated/tests/test_unpublished_branch.py
+++ b/openpilot/system/updated/tests/test_unpublished_branch.py
@@ -38,7 +38,7 @@ class TestUnpublishedBranch(unittest.TestCase):
     def run(command, cwd):
       self.assertEqual(cwd, str(self.merged))
       self.commands.append(command)
-      if command == ["git", "ls-remote", "--heads"]:
+      if command == ["git", "ls-remote", "--heads", "origin"]:
         return self.remote_heads
       if command == ["git", "ls-remote", "origin", "HEAD"]:
         return f"{REMOTE}\tHEAD\n"
@@ -55,7 +55,7 @@ class TestUnpublishedBranch(unittest.TestCase):
     self.assertFalse(self.updater.update_ready)
     self.assertFalse(self.updater.fetch_update())
     self.assertNotIn(TARGET, self.updater.branches)
-    self.assertEqual(self.commands.count(["git", "ls-remote", "--heads"]), 1)
+    self.assertEqual(self.commands.count(["git", "ls-remote", "--heads", "origin"]), 1)
     self.updated.set_consistent_flag.assert_not_called()
     self.assertNotIn("UpdaterState", self.updater.params.values)
 
@@ -94,7 +94,7 @@ class TestUnpublishedBranch(unittest.TestCase):
     self.assertTrue(self.updater.update_available)
 
     def failed_run(command, cwd):
-      if command == ["git", "ls-remote", "--heads"]:
+      if command == ["git", "ls-remote", "--heads", "origin"]:
         raise subprocess.CalledProcessError(128, command, output="network failed")
       return f"{REMOTE}\tHEAD\n"
 
diff --git a/openpilot/system/updated/updated.py b/openpilot/system/updated/updated.py
index bca8b62f5e..e57599fd57 100755
--- a/openpilot/system/updated/updated.py
+++ b/openpilot/system/updated/updated.py
@@ -45,11 +45,15 @@ class UserRequest:
   NONE = 0
   CHECK = 1
   FETCH = 2
+  FAST = 3
 
 class WaitTimeHelper:
   def __init__(self):
     self.ready_event = threading.Event()
     self.user_request = UserRequest.NONE
+    self.request_lock = threading.RLock()
+    self.request_generation = 0
+    self.fast_target = None
     signal.signal(signal.SIGHUP, self.update_now)
     signal.signal(signal.SIGUSR1, self.check_now)
     self.control = UpdaterControlServer(self._control_request)
@@ -60,24 +64,39 @@ class WaitTimeHelper:
     else:
       atexit.register(self.control.close)
 
-  def _control_request(self, action: str) -> None:
-    if action == 'check':
-      self.user_request = UserRequest.CHECK
-    elif action == 'download':
-      self.user_request = UserRequest.FETCH
-    else:
-      return
-    self.ready_event.set()
+  def _request(self, request: int, *, branch=None, commit=None) -> None:
+    with self.request_lock:
+      self.user_request = request
+      self.fast_target = (branch, commit) if request == UserRequest.FAST else None
+      self.request_generation += 1
+      self.ready_event.set()
+
+  def _control_request(self, action: str, *, branch=None, commit=None) -> None:
+    request = {'check': UserRequest.CHECK, 'download': UserRequest.FETCH, 'fast': UserRequest.FAST}.get(action)
+    if request is not None:
+      self._request(request, branch=branch, commit=commit)
 
   def update_now(self, signum: int, frame) -> None:
     cloudlog.info("caught SIGHUP, attempting to downloading update")
-    self.user_request = UserRequest.FETCH
-    self.ready_event.set()
+    self._request(UserRequest.FETCH)
 
   def check_now(self, signum: int, frame) -> None:
     cloudlog.info("caught SIGUSR1, checking for updates")
-    self.user_request = UserRequest.CHECK
-    self.ready_event.set()
+    self._request(UserRequest.CHECK)
+
+  def current_request(self) -> tuple[int, int, tuple[str, str] | None]:
+    with self.request_lock:
+      self.ready_event.clear()
+      return self.user_request, self.request_generation, self.fast_target
+
+  def finish_request(self, generation: int) -> bool:
+    with self.request_lock:
+      if self.request_generation != generation:
+        return False
+      self.user_request = UserRequest.NONE
+      self.fast_target = None
+      self.ready_event.clear()
+      return True
 
   def sleep(self, t: float) -> None:
     self.ready_event.wait(timeout=t)
@@ -374,15 +393,14 @@ class Updater:
 
     excluded_branches = ('release2', 'release2-staging')
 
-    try:
-      run(["git", "ls-remote", "origin", "HEAD"], OVERLAY_MERGED)
-      self._has_internet = True
-    except subprocess.CalledProcessError:
-      self._has_internet = False
-
     self._branches_checked = False
     setup_git_options(OVERLAY_MERGED)
-    output = run(["git", "ls-remote", "--heads"], OVERLAY_MERGED)
+    try:
+      output = run(["git", "ls-remote", "--heads", "origin"], OVERLAY_MERGED)
+    except subprocess.CalledProcessError:
+      self._has_internet = False
+      raise
+    self._has_internet = True
 
     self.branches.clear()
     for line in output.split('\n'):
@@ -403,6 +421,35 @@ class Updater:
     else:
       cloudlog.info(f"up to date on {cur_branch} ({str(cur_commit)[:7]})")
 
+  def fast_update(self, branch: str, commit: str) -> str:
+    from openpilot.starpilot.drive_state.evidence import PhysicalSource
+    from openpilot.starpilot.software.fast_update import fast_update
+
+    source = PhysicalSource()
+
+    def parked():
+      deadline = time.monotonic() + 0.75
+      while True:
+        if (self.params.get_bool("IsOffroad") and not self.params.get_bool("IsOnroad") and
+            source.allowed() and source.effective() is False):
+          return True
+        if time.monotonic() >= deadline:
+          return False
+        time.sleep(0.02)
+
+    def invalidate():
+      Path(FINALIZED, ".overlay_consistent").unlink(missing_ok=True)
+      OVERLAY_INIT.unlink(missing_ok=True)
+      dismount_overlay()
+      self.params.put_bool("UpdateAvailable", False, block=True)
+      self._branches_checked = False
+
+    try:
+      return fast_update(Path(BASEDIR), branch, expected_commit=commit, params=self.params, parked=parked,
+                         current_os=HARDWARE.get_os_version(), invalidate=invalidate)
+    finally:
+      source.close()
+
   def fetch_update(self) -> bool:
     if not self._branches_checked:
       self.check_for_update()
@@ -475,7 +522,7 @@ def main() -> None:
       params.put("InstallDate", t, block=True)
 
     updater = Updater()
-    update_failed_count = 0 # TODO: Load from param?
+    update_failed_count = max(0, params.get("UpdateFailedCount") or 0)
     wait_helper = WaitTimeHelper()
 
     # invalidate old finalized update
@@ -487,39 +534,47 @@ def main() -> None:
     # Run the update loop
     first_run = True
     while True:
-      wait_helper.ready_event.clear()
+      requested, request_generation, fast_target = wait_helper.current_request()
 
       # Attempt an update
       exception = None
+      fast_requested = requested == UserRequest.FAST
       try:
-        # TODO: reuse overlay from previous updated instance if it looks clean
-        init_overlay()
-
-        # ensure we have some params written soon after startup
-        updater.set_params(False, update_failed_count, exception)
-
-        if not system_time_valid() or first_run:
-          first_run = False
-          wait_helper.sleep(60)
-          continue
-
-        update_failed_count += 1
-
-        # check for update
-        params.put("UpdaterState", "checking...", block=True)
-        updater.check_for_update()
-
-        # download update
-        last_fetch = params.get("UpdaterLastFetchTime")
-        timed_out = last_fetch is None or (datetime.datetime.now(datetime.UTC).replace(tzinfo=None) - last_fetch > datetime.timedelta(days=3))
-        user_requested_fetch = wait_helper.user_request == UserRequest.FETCH
-        if params.get_bool("NetworkMetered") and not timed_out and not user_requested_fetch:
-          cloudlog.info("skipping fetch, connection metered")
-        elif not download_permitted(params, manual=user_requested_fetch, check_only=wait_helper.user_request == UserRequest.CHECK):
-          cloudlog.info("skipping fetch, check-only request or automatic downloads disabled")
+        if fast_requested:
+          update_failed_count += 1
+          params.put("UpdaterState", "updating...", block=True)
+          updater.fast_update(*fast_target)
+          write_time_to_param(params, "UpdaterLastFetchTime")
+          write_time_to_param(params, "LastUpdateTime")
         else:
-          if updater.fetch_update():
-            write_time_to_param(params, "UpdaterLastFetchTime")
+          # TODO: reuse overlay from previous updated instance if it looks clean
+          init_overlay()
+
+          # ensure we have some params written soon after startup
+          updater.set_params(False, update_failed_count, exception)
+
+          if not system_time_valid() or first_run:
+            first_run = False
+            wait_helper.sleep(60)
+            continue
+
+          update_failed_count += 1
+
+          # check for update
+          params.put("UpdaterState", "checking...", block=True)
+          updater.check_for_update()
+
+          # download update
+          last_fetch = params.get("UpdaterLastFetchTime")
+          timed_out = last_fetch is None or (datetime.datetime.now(datetime.UTC).replace(tzinfo=None) - last_fetch > datetime.timedelta(days=3))
+          user_requested_fetch = requested == UserRequest.FETCH
+          if params.get_bool("NetworkMetered") and not timed_out and not user_requested_fetch:
+            cloudlog.info("skipping fetch, connection metered")
+          elif not download_permitted(params, manual=user_requested_fetch, check_only=requested == UserRequest.CHECK):
+            cloudlog.info("skipping fetch, check-only request or automatic downloads disabled")
+          else:
+            if updater.fetch_update():
+              write_time_to_param(params, "UpdaterLastFetchTime")
         update_failed_count = 0
       except subprocess.CalledProcessError as e:
         cloudlog.event(
@@ -536,14 +591,23 @@ def main() -> None:
         OVERLAY_INIT.unlink(missing_ok=True)
 
       try:
-        params.put("UpdaterState", "idle", block=True)
         update_successful = (update_failed_count == 0)
-        updater.set_params(update_successful, update_failed_count, exception)
+        if fast_requested:
+          params.put("UpdateFailedCount", update_failed_count, block=True)
+          if exception is None:
+            params.remove("LastUpdateException")
+          else:
+            params.put("LastUpdateException", exception.encode("utf-8")[:4096].decode("utf-8", errors="ignore"), block=True)
+          params.put("UpdaterState", "updating..." if params.get_bool("DoReboot") else "idle", block=True)
+        else:
+          params.put("UpdaterState", "idle", block=True)
+          updater.set_params(update_successful, update_failed_count, exception)
       except Exception:
         cloudlog.exception("uncaught updated exception while setting params, shouldn't happen")
 
       # infrequent attempts if we successfully updated recently
-      wait_helper.user_request = UserRequest.NONE
+      if not wait_helper.finish_request(request_generation):
+        continue
       wait_helper.sleep(5*60 if update_failed_count > 0 else 1.5*60*60)
 
 
diff --git a/scripts/laptop_device_build.sh b/scripts/laptop_device_build.sh
index 7df6e07cc4..f010868f0c 100755
--- a/scripts/laptop_device_build.sh
+++ b/scripts/laptop_device_build.sh
@@ -616,6 +616,7 @@ run_larch64_build() {
   # QCOM-compiled driving/DM models and both camera warp families.
   python3 -m tools.laptop_device_build.package_model_chunks --source "${ROOT_DIR}/openpilot/selfdrive/modeld/models" --destination "${ROOT_DIR}/openpilot/selfdrive/modeld/models"
   verify_device_artifacts
+  python3 "${ROOT_DIR}/openpilot/common/prebuilt_manifest.py" "${ROOT_DIR}"
   touch "${ROOT_DIR}/prebuilt"
 }
 
diff --git a/scripts/native_device_build.sh b/scripts/native_device_build.sh
index 7b4674adf1..6be6a9b6e7 100755
--- a/scripts/native_device_build.sh
+++ b/scripts/native_device_build.sh
@@ -55,6 +55,7 @@ case "${mode}" in
     fi
     python3 -m tools.laptop_device_build.package_model_chunks --source "${ROOT_DIR}/openpilot/selfdrive/modeld/models" --destination "${ROOT_DIR}/openpilot/selfdrive/modeld/models"
     python3 "${ROOT_DIR}/tools/laptop_device_build/validate_artifacts.py" "${ROOT_DIR}"
+    python3 "${ROOT_DIR}/openpilot/common/prebuilt_manifest.py" "${ROOT_DIR}"
     touch prebuilt
     ;;
   *)