hi all, my rom is a vendor rom and i want to flash an official one. i received permission for unlocking the mi mix and i downloaded miunlock app. i put the phone in fastboot mode but the mi-unlock is stuck at 50% saying after that caouldn't verify the phone. i installed usb drivers and i disabled digital drivers security check in windows 10 but no effect.moreover, after 10 seconds the phone exits fastboot and starts only charging. what else i can do?