Because most ISPs use TR-069 (CWMP), your ZTE ZXHN F670L will likely receive automatic ZTE ZXHN F670L EPON firmware updates silently at 2 AM. However, if you own your ONT (purchased independently) or use a smaller ISP that does not maintain auto-updates, you must manually check every 6-12 months.
Pro Tip: Disable "Auto-update" only if you have a critical business application that cannot tolerate a 3-minute reboot window. Otherwise, let the ISP handle it. zte zxhn f670l epon firmware
If your ISP has a customer support portal, search for "Downloads" or "ONT Firmware." Some progressive ISPs provide .bin files for manual flashing. Because most ISPs use TR-069 (CWMP), your ZTE
There is no open-source firmware (OpenWrt, DD-WRT) for the F670L due to proprietary Broadcom or ZTE chipsets and lack of GPL source release. The best you can do: Otherwise, let the ISP handle it