mg4/OTA.md

Publishing an OTA release

How to ship an update the car will install by itself. Written for whoever does this next — probably me, having forgotten the details.

What the updater actually looks for

OtaUpdater.check() reads https://api.github.com/repos/fatihdonmezdev/MG4ABRP/releases and walks every entry, keeping the highest version rather than the first match. A release is a candidate only if all of these hold:

Requirement	Where it is enforced	What happens otherwise
Marked pre-release	release.optBoolean("prerelease")	Skipped entirely
Asset name contains unstable	name.contains("unstable")	Asset ignored
Asset name ends -<version>.apk	ASSET_VERSION regex	No version, asset ignored
Version strictly higher than installed	isNewer()	Nothing to do, reports "Güncel"
Download host on the allowlist	isAllowedUrl()	Refused and logged
APK signed with the same certificate as the running app	signatureMatchesRunningApp()	Deleted, never installed

The last one is the one that bites. The car runs a platform-signed build; an APK signed with a debug key — or anyone else's key — is downloaded, rejected and deleted. Sign every release with the same platform key or the update silently never lands.

The version comes from the asset filename, not the git tag. The tag can stay unstable forever and be moved; the filename is what identifies a build.

Release checklist

1. Raise the version. app/build.gradle, defaultConfig:

   versionCode 20          // must increase — Android orders updates by this, not by name
   versionName "2.2.3"
   

   The unstable flavour appends its own suffix, so 2.2.3 becomes 2.2.3.0-unstable. Check what the installed build reports before picking a number: the app's About dialog shows it, and isNewer compares numerically segment by segment.

2. Build.

   ./gradlew :app:assembleUnstableDebug
   

3. Sign with the platform key. Options come before the input APK — apksigner rejects the other order.

   BT=~/Android/Sdk/build-tools/35.0.0
   KEYS=~/Desktop/Coding/MG/DriveHub_Kamera/tools
   
   "$BT/zipalign" -f 4 \
     app/build/outputs/apk/unstable/debug/app-unstable-debug.apk aligned.apk
   
   "$BT/apksigner" sign \
     --key  "$KEYS/platform.pk8" \
     --cert "$KEYS/platform.x509.pem" \
     --out  FatihsMG4-unstable-2.2.3.apk \
     aligned.apk
   
   rm aligned.apk
   

   The output filename is the version the updater reads. Name it FatihsMG4-unstable-<version>.apk and nothing else.

4. Verify the signer before uploading. It must say CN=Android:

   "$BT/apksigner" verify --print-certs FatihsMG4-unstable-2.2.3.apk | grep DN:
   

5. Publish. On github.com/fatihdonmezdev/MG4ABRP → Releases → Draft a new release:

   • tag: unstable (reuse it; the rolling tag is the design)
   • tick "Set as a pre-release" ← the whole thing is inert without this
   • attach the signed APK

6. Install it. Open the app on the head unit and press the refresh button in the top bar. Expected toast: Güncellendi: 2.2.3 — yeniden başlatın.

When it says something else

Toast	Meaning
Güncel (2.2.2.0-unstable)	No release beat the installed version. Check the pre-release tick and the asset filename.
İndirme başarısız	Release found, download did not complete. Usually no network.
Kuruluyor: 2.2.3 — ekrandaki onayı bekleyin	The session was committed. Not done yet: watch for the platform's own toast, or a confirmation dialog to accept.
Kurulum reddedildi: imza uyuşmuyor	Genuinely the wrong key — rebuild and re-sign with platform.pk8. Unlike the old catch-all, this one means what it says.
Kurulum reddedildi: APK okunamadı	The archive does not parse, or it is built for another package.
Kurulum başlatılamadı … Log sayfasına bakın	The session could not be created or committed. adb logcat -s EVABRP.Update.
Kurulum başarısız: INSTALL_FAILED_…	From OtaInstallResultReceiver — the package manager's own words for why it refused.
Güncelleme kontrolü başarısız	The check threw. adb logcat -s EVABRP.Update OtaUpdater if a cable is available; otherwise the in-app Log page.

How the install works, and why it is not pm install

OtaUpdater.install() used to shell out to /system/bin/pm install -r. On this head unit that fails every time, and the reason is worth writing down because the symptom pointed somewhere else entirely.

The downloaded APK lives in context.getCacheDir(). pm does not install the file itself — it passes the path to the package manager service, which opens it from its process and SELinux context, where an app's private cache is not readable. The install failed, and because install() returned a bare boolean, the caller reported the only failure it knew how to name: Kurulum reddedildi (imza uyuşmuyor?). A correctly signed build, refused with a signature error it had not earned. The pm output that would have said so was captured and thrown away.

It now uses the platform PackageInstaller: we open the archive ourselves and stream it into a session, so no second process ever has to read our cache. The approach is taken from merthankaraman/DriveHub_Dort, which hit the same wall on the same hardware.

Two consequences for anyone reading a failure:

• Committing a session is not installing. commit() is asynchronous. The refresh button can only report that an install started; the verdict arrives at OtaInstallResultReceiver and appears as its own toast.
• STATUS_PENDING_USER_ACTION is not an error. The platform is asking the driver to confirm. The receiver launches the confirmation activity the platform hands it.

Still unverified on the car: whether this build installs silently or raises that confirmation. Either way it installs, which the old path did not.

Why the check is manual

The refresh button is the only trigger. UpdateHook.checkInBackground(this) also runs on app start, but the app is rarely launched — the upload service does the work, and the driver does not open the UI on every trip. The button is there so an update can be pulled deliberately rather than waiting for a launch that may not come.

The upload service does not check for updates on its tick. Installing a new APK restarts the process, and doing that mid-drive would interrupt the telemetry the service exists to send.