For ISPs or enterprise admins, upgrades are often pushed from the OLT side using CLI commands. Load the firmware onto the OLT via TFTP or FTP.

: Use a standard Ethernet cable to connect your PC's LAN port directly to one of the ONT's LAN ports (usually LAN1).

— Powerful but not for beginners. With proper precautions, it’s the go-to solution for advanced ONT firmware management.