If this doesn't work, your device is locked and requires one of the following methods.

This guide is for educational purposes. Modifying your router’s firmware may violate your agreement with your ISP. The author is not responsible for any damage to your device.

In the TFTP server tool, set the "Current Directory" to the folder containing your firmware binary file.

Pursuing a "new" unlock firmware is an advanced path for enthusiasts and tinkerers. It offers the chance to completely overhaul your device but comes with a real risk of permanently damaging it.

| Feature | Old (Code Unlock) | New (Firmware Unlock) | |--------|------------------|------------------------| | Permanence | Yes, but code can be lost | Yes, system-wide | | Risk | Low | Medium (potential brick) | | Band unlock | No | Sometimes included | | SIM swap | Works after code entry | Works instantly | | Warranty | Void (same) | Void (same) |

Backup current firmware and configuration

Launch your chosen flashing software (e.g., ZTE Terminal Tool) as an Administrator.

Most ZTE flashing tools (like ZTE Sales Terminal Flash Tool or Miflash) run natively on Windows 7, 10, or 11.

The router will start downloading the firmware from the TFTP server.