I have the exact same issue as @owd200. Installed UT following the instruction. Everything went flawless.

But reverting it is just not possible. In terminal or command-line adb recognizes the phone, but neither in Windows nor Linux it is possible to enter the bootloader/fastboot from there --> permission denied.

Via the phone terminal like @tafitson recommended is possible, but the phone is no longer detected via adb via computer.

When entering recovery from bootloader, in the advanced option, it's possible to activate adb and it's recognized by my computer. Nonetheless it's not the bootloader/fastboot; so flashing is still not possible.

Also trying to enter fastboot mode from the recovery unfortunately ends in an complete freeze.

Anyone solved that problem so far?