Broken on Android 16 (LineageOS 23) and potential workaround

[technopagan]

Due to the changes of Google to the Device Owner provisioning, sadly this app has stopped working as intended. Biometric auth is still possible from lock-screen. :(

Even if the app got updated to deal with DevicePolicyManagerService, Google's more restrictive policy means that (in theory) any device must NOT have any accounts registered at the moment Device Owner is granted.

A potential workaround for those of us willing to re-flash our ROM might therefore be:

• Flash the ROM (e.g. LineageOS 23)
• Go through initial setup without adding any accounts
• Install AdminControl: F-Droid or sideload via adb install AdminControl.apk
• Run: adb shell dpm set-device-owner com.davidshewitt.admincontrol/.ControlDeviceAdminReceiver
• Only afterwards, add your accounts and set up everything else

I've also asked the great Slop Machine to generate a PR to update the app's code base so that (after granting the device owner permission once without registered accounts) it continues to work on Android 16 / LineageOS 23. Since I have little Android Studio experience, I haven't tested this. But I'm leaving it here for reference.

android16-compatibility.zip

[linux-colonel]

Hi @technopagan,

Thanks for looking into this. I haven't worked on this app for years and I'm surprised it still works at all! When I have time I'll test out your code. If you could open a PR instead of having a zip file that would make things easier for me.

Thanks!

-- linux-colonel

[technopagan]

The reason why I was still / again using this app was to prevent fingerprint unlock being available on the lockscreen, but retain its functionality once the device had been unlocked.

The sad necessity of this was caused by government(s) making forcibly pressing your fingertip to your phone by local police legal while still retaining the requirement of a judge's warrant to demand your passphrase. The world we live in ...

Good news, however: LineageOS 23 (Android 16) now has a toggle-switch under "Fingerprint" to disable unlocking the device with it while retaining its functionality inside apps. So EXACTLY what I was using AdminMode for until LineageOS22 / Android 15.

So I would consider my case closed. Feel free to use the code bundle to update the app for Android 16 compatibility, of course. But Android 16's more restrictive Device Owner provisioning will probably limit this app's usefulness to "right after fresh ROM installation".

Thanks for keeping my device safer until now!