I have re flashed flyme 6, and downgraded to flyme 5, then flashed the unlocked bootloader,then flashed UB, some times It will not go past the UB,recovery screen, I have then flashed twrp wiped, then flash a twrp made restore of UB,then flashed UB recovery to get a working OTA,and then updated.
I have done this with ch/en, flyme.
I quess,adb,is not,recognized sometimes