Hi my friend has a Note 2 who has a very old Android version. Some apps can't be installed without upgrading the system. I downloaded a custom ROM (Resurrection Remix Android 7.1.2 Nougat) and helped him to flash to upgrade. However some apps limited the functionality or refused to run. I believe it has to do with the fact it is a custom ROM. How could I solve the problem? It doesn't matter what ROM to upgrade, as long as: 1. it is stable 2. Android 6 or above (he wants permission manager, preferably with Privacy Guard) 3. can pass SafetyNet and any popular ways app use to detect a custom ROM Thank you.