Before flashing, download the official Huawei B311-221 firmware from a backup server. Keep it safe. You will need it if you ever want to revert.
"SIM Card Invalid," blinked the red LED status light. huawei router b311221 unlock firmware patched
The term "Patched Firmware" refers to a modified version of the Huawei stock firmware ( B311-221_firmware.bin ) that has been to bypass security checks. huawei router b311221 unlock firmware patched