, please note: ZTE firmware files are typically proprietary, region-locked (e.g., India, LATAM, Philippines), and not publicly distributed by ZTE. Upgrading without the correct file from your ISP can brick the device.

Assuming the upgrade process has completed, follow this : 1. Immediate Post-Reboot Checks (First 5 minutes) After the device reboots automatically (or manually after upgrade):

To provide an accurate for the ZTE F680 (a common GPON ONT/ONU), I need to assume you have already successfully uploaded and applied the firmware file (e.g., via the web interface at 192.168.1.1 with admin credentials).

| Check | Action | |-------|--------| | | Should be solid green. Blinking indicates boot loop (failed upgrade). | | PON/Optical LED | Should be solid green (registered with OLT). Blinking/flashing means loss of signal or OLT rejection. | | LAN LED (connected PC) | Should flash on data activity. | | Internet LED (if present) | Should be solid green or blue. | If PON LED is blinking after upgrade → The new firmware may have changed the ONU’s serial number or software version mismatch with ISP’s OLT. You may need to re-register the device with your ISP. 2. Factory Reset (Strongly Recommended) A firmware change can leave old configurations (VLANs, PPPoE credentials, TR-069 settings) corrupted.