Advertisements I can only confirm that you can run in UBT on the latest firmware without any problems. Press the reset button, connect to the computer and after 10 sec. release the button. Not quite so, this is a user-debug firmware with full root access from adb and shell, with the ability to mount -o remount,rw / and disable verity. P.S. There is no way to return to the stock user firmware. PP.SS. It is built on the basis of beta firmware 5211, there is already an adaptive DV and HDR mode and has the number 5222.