The firmware is hardware- and carrier-specific. Using a wrong link will almost certainly brick the device.
The process takes roughly 3 to 5 minutes. The router will automatically reboot when finished. 4. Troubleshooting Common Issues zte mf10 upgrade firmware link
Remove your 3G/4G USB dongle from the router's USB port before starting the upgrade. The firmware is hardware- and carrier-specific
Here is the direct link to download the latest firmware for ZTE MF10: zte mf10 upgrade firmware link