Hi welcome to jme community, why you want to use the app as a system app ?
Some functions may not work properly when the app is a system app including the android application files reader used by jme, so its not recommended to do so, there would be adverse effects, and doing so in Manifest won’t make the app “a system app”.
Check this :
That would probably mean that if you have changed the user app ID, then you cannot access the game package resources & files which in turn would violate the use of Assets & AssetManager.
BTW, app can be settled as system app easily through rooted devices, but that also disrupts the behavior of the app, as setting the app as a system app does nothing but copying the package to the system !
How to deal with this :
- remove the uid flag.
- Better use the Android Intents, Services, ContentProviders & JobSchedulers to communicate with other apps & system apps within your app, w/o changing your user id or setting the app as system app.