Some newer versions (2021+) have a locked bootloader that prevents USB flashing.
Use a tool like Huawei Update Detection or Balong Flash to push the firmware via the USB port. ⚠️ Important Troubleshooting huawei b311s220 unlock firmware upd
Updating the Huawei B311s-220 with unlock firmware is the best way to get the most out of your hardware. By moving to a "General" firmware, you gain freedom of carrier choice and access to advanced network configuration tools. Some newer versions (2021+) have a locked bootloader
Before flashing new software, you must verify your hardware. The B311s-220 is a single-band (2.4GHz) router that supports LTE Cat4. B311s-220 huawei b311s220 unlock firmware upd
If the web method fails, you must use the "Balong USB Downloader" tool: