Android development RecoverySystem.installPackage() cannot write to /cache/recovery/command permission denied

Question

I have been asked to write a small simple app for an Android-based product. The device comes with two Android system images with different features. The app I\'m writing is

Answer 1

I met the same problem in android 8.
If you add android:sharedUserId="android.uid.system" in AndroidManifest.xml, it should work.