: Place a SIM card from a different network into the router. Access the Web Interface

| Error | Cause | Solution | | :--- | :--- | :--- | | | Windows 11 signed driver enforcement | Reboot Windows → Disable Driver Signature Enforcement → Reinstall drivers | | "Flashing stuck at 99%" | USB power fluctuation | Re-flash. Use a powered USB hub. | | Router dead after flash | Bootloader mismatch | Re-enter USB Download mode. Flash a "Full Firmware" (not just an update). | | No 4G, only 3G | Firmware overwrote band settings | Use the unlocked menu to force LTE bands appropriate for your country. | | Password unknown | Firmware set a default | Try user / user or check the sticker on the router base. |

is a specific hardware revision, using firmware designed for other B311 variants (like the B311s-220) can "brick" the device, rendering it permanently unusable. Firmware Compatibility

A high-quality USB-to-Micro-USB or USB-to-USB cable (depending on your specific hardware revision).