If the tool fails to find your device, check your Windows Device Manager. Look for missing drivers under "Ports (COM & LPT)" or "Other Devices". Reinstall the ZTE USB Drivers and try a different USB port.
For many older or specialized ZTE modems (like the Telstra-branded MF636 or MF627), ZTE and its partners have released standalone upgrade tools. These are executable programs designed for a specific modem model and are often used for major software overhauls. For instance, the manual for the MF636 modem specifies the use of an upgrade tool called MF636 Telstra Series 7 Update Tool that directly flashes the new firmware onto the device. Zte Modem Firmware Update Tool
Run the application as an Administrator (right-click the .exe and select "Run as administrator"). If the tool fails to find your device,
Follow the on‑screen instructions. The tool will typically detect your connected USB modem and guide you through the flashing process. For many older or specialized ZTE modems (like
: Sometimes used by advanced users to flash firmware if the device is in "Qualcomm Mode". Vital Precautions
Do modems need updates too and need to be changed to stay secure