Go to Maintenance > Device Management > Software Upgrade or Firmware Update . The exact path varies by repack, but it is typically under "System Tools."

: After making modifications, you'll need to repack the firmware into its original format. This involves compressing the modified files back into a single file that the device can recognize and flash.

Modified firmware carries a high risk of making the router unusable. Always ensure you have a way to recover (like serial/TTL access) before flashing. Do you have a specific feature

: Never update via Wi-Fi; use a LAN cable to prevent connection drops that can brick the device. Check Hardware Version

Assume you have zte_f671y_v2.0.1_ISP.bin .