If your router cannot reach the update server or if you have downloaded a specific firmware package from ZTE's official support site, follow these steps:
Try a hard factory reset. Press and hold the physical Reset button on the back of the router using a paperclip for 10–15 seconds while the device is powered on. Release it and wait for the system to initialize. "No Update Available" Message update software in zte mf297d
Use this method if you have downloaded a specific firmware file from the official ZTE support site Download Firmware If your router cannot reach the update server