Bootloader was probably re locked. That is the only reason one can't flash a rom in fastboot. They then needed to rerun the MiUlock tool and re-unlock bootloader and the use the MiFlash tool or install TWRP and flash Xiaomi.eu rom. The other things to try if your phone is stuck in fastboot and non responsive are:Yes, fine.
But this OP had fastboot access but no way to flash fastboot rom.
What's your opinion about?
- Press and hold the power key for at least 12 seconds
When the device gets stuck on the fastboot screen, the first reaction will be to power it down, so you press the power key for a few seconds but it won’t respond. The thing is you need to press and hold the power key for at least 12 seconds.
As you can see, it takes about 12 seconds before the screen turns off, and around 14 seconds before the Redmi text shows. That's a sign that the phone will now boot up normally.
Most of the similar cases I’ve encountered have been fixed by this very simple procedure. So if you experience a similar issue, hold the power key long enough to trigger the phone to reboot.
However, if your device is still not responding after holding the power key for 12 seconds or more, then you should try the next solution.
- Force start your device: If for some reason your phone is still stuck on the fastboot screen even after doing the first solution, then it’s time you do the forced restart, or the simulated battery removal.
1. Press the volume up, volume down and power keys at the same time, and hold them together for 12 seconds. This will trigger the phone to power down and turn back up.
2. When the Mi text shows, release the keys and wait for your phone to finish the reboot.