Some F670L units have a hidden TFTP recovery. Use tftp -i 192.168.1.1 PUT firmware.bin after power cycling with reset.
# Login telnet 192.168.1.1
Unlike consumer routers purchased at retail stores, ONTs like the F670L are usually "locked down" by the ISP. The firmware controls the GPON/EPON authentication process (via Serial Number or SLID/Password). The search for "exclusive" firmware usually stems from a desire to use the device on a different fiber network or to enable features disabled by the provider. zte zxhn f670l epon firmware exclusive
Unauthorized firmware might fail to register properly on strict OLTs due to authentication mismatches. Some F670L units have a hidden TFTP recovery
While official "offline download packages" are sometimes available on the ZTE Support site , custom open-source firmware for this specific model remains rare due to the proprietary nature of the GPON chipset. zte zxhn f670l epon firmware exclusive