B311-221 Unlock Firmware -

: This indicates a failed flash or a corrupted firmware file. Retry the process using a different version of the unlock firmware.

Do you have a and a USB male-to-male cable ready? B311-221 Unlock Firmware

: Once completed, perform a Factory Reset to clear old carrier settings. Verifying the Update : This indicates a failed flash or a corrupted firmware file

Some firmware versions have hidden http://192.168.8.1/html/unlock.html – try: B311-221 Unlock Firmware

Alternative: Use a (e.g., UnlockBase, RouterUnlock).