Test security, hardware, communication and update behavior before trusting a new operating system.

Security checks

Confirm screen lock, device encryption, security patch level, SELinux state where documented, verified-boot status, update source and whether the bootloader should remain locked or unlocked.

Review installed packages and permissions before restoring private data.

Hardware and network checks

Test calls, emergency calling where safely possible, SMS, mobile data, Wi-Fi, Bluetooth, GPS, NFC, USB, charging, cameras, microphone, speakers, biometrics and sensors.

Run tests before and after restoring apps so you can distinguish ROM problems from application conflicts.

Update rehearsal

Read the project’s update instructions, confirm whether add-ons survive OTA updates, and keep a current rollback package. Never install an update when the battery is low or backups are stale.

Critical safety boundary

Unlocking and flashing can erase data, weaken device security, disable protected services or make a phone unbootable. Use only your own device, exact model-specific instructions and a tested stock restore path.

Official and primary sources

35 · Custom ROMs and Android System Modding

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