I have the same problem. When i try to use the updater app on the phone i get Can't verify update to go from stable to developer rom. And thats probably the reason why i can't use Mi unlock. I get an error: Mi unlock stuck on 50 % and couldn't verify device. I tried the Xiaomi mi flash beta but get an error flash_all_except_data_storage Dot bat cannot be found. Someone has any instructions?
I tried using your method and everything went well until MiFlash gave an error saying not enough storage available. This was while it was already at 10%. The phone is now only shows the Mi logo and won't go into download or recovery mode. Any advive?
When i press and hold vol + and vol - i get the Mi phone with the connector disconnected at the bottom.
Then when i connect the cable it goes to connected. But then the phone doesnt show up in device manager or in Mi flash. I am using Windows 10 64 bit with Driver signing off.
I am getting a message: Try in normal mode first than switch. When trying mi Pc suite and phone in fastboot. The screen with the phone and the cable disconnected is it that the bootloader is locked?