Can I make /system writable on Android devices?

Yes, on userdebug and engineering builds.

By design, production Play Protect Certified Android builds ship with /system mounted read-only and protected by dm-verity. This ensures the partition can’t be tampered with, maintaining the integrity of the OS. On non-production builds, however, you can temporarily disable verity and remount /system as read-write in order to make changes.

Steps

1. Connect via ADB and disable verity:

adb root
adb disable-verity
adb reboot

2. After reboot, remount /system:

adb root
adb remount
adb shell
mount -o rw,remount /system

At this point /system is writable and you can make modifications.

1. Once finished, re-enable verity:

adb root
adb enable-verity
adb reboot

Considerations

• This only works on userdebug or engineering builds. Retail/production builds won’t permit it.
• Any changes may be lost after an OTA update, if it remains possible to do so.
• Leaving verity disabled weakens device integrity. Always re-enable once done.
• Mistakes in /system can break the OS or prevent booting, so proceed with caution.

This approach is intended for development and testing. For production devices, modifying /system is not supported.