Samsung has recently (with Android 9 update) introduced a new obstacle to flashing custom binaries on their devices. After unlocking the device with a new process (described here), you get the impression that the bootloader is unlocked, but it’s not!
In reality, the bootloader is unlocked, but a new service on the device, the “VaultKeeper”, does not allow flashing, due to the possibility that remote management will forbid it, for example if the device is bought on a carrier subsidy, and the user attempts to unlock it, or if the device is provisioned remotely by the employer.
If you attempt to flash a custom binary while the bootloader is unlocked but VaultKeeper is not released, your device will be switched to “RMM STATE: Prenormal” which will prevent any flashing of any binaries for a week or more. If this happens, you will have to wait the defined time, which is not written anywhere – so you have to keep trying every day, or use a paid tool to reset the state.
However, if you have just unlocked your device, and have not yet tried to unlock it, you can easily prevent this from ever happening. Follow the directions below:
- Unlock the bootloader as described in this post
- Boot into the OS and connect the device to the Internet
- Setup the device fully, preferably with a Google Account that you used before
- Go into Developer options (tap Build number 5 times), and verify that the OEM Unlocking options exists, it is turned on and it is greyed out (cannot be changed). Opening this screen will enable VaultKeeper to verify the device integrity and to check if it is managed remotely and disabled.
- Reboot the device into the OS once more to ensure that VaultKeeper has removed the lock on flashing in the bootloader.
- Reboot the device into download mode with adb reboot download.
- Your device is now ready to accept unofficial images via Odin
If you encounter any issues, do not hesitate to comment below, and I will try to help you resolve them.
Please note, if your device is already in “RMM STATE: Prenormal”, I cannot help you!