Use this method if you have already downloaded a specific firmware file from an official source like the ZTE Support Portal or your Internet Service Provider (ISP). Update ZTE F660 Firmware, How To - HardReset.info
No – if your device is managed via TR-069, the ISP will deploy firmware. Manual upgrades are only for unlocked or out-of-support units. Zte F660 Firmware Upgrade Download
If you see U-Boot 1.1.4 , you are on an old flash layout. Do not mix firmware types. Use this method if you have already downloaded
| Item | Action | |------|--------| | | Do not upgrade over Wi-Fi. One power flicker will corrupt the flash. | | UPS or stable power | A power outage during write will brick the device. | | Backup of settings | Admin → Backup/Restore → Save configuration to .bin file. | | ISP credentials | Know your VLAN ID (e.g., 1101), PPPoE username/password, VoIP SIP details. | | Factory reset | Optional but recommended: Reset to factory defaults before upgrade. | If you see U-Boot 1