Based on internet archives and technical forums, several firmware versions exist, differentiated by region and software stack:
Connect your computer directly to the ONT’s LAN port using an . Do not attempt a firmware update over Wi-Fi. Access the gateway page in your browser. Go to Management / System Tools > Firmware Upgrade . Firmware Gm220-s
One FXS RJ11 Plain Old Telephone Service (POTS) port for VoIP alongside a single USB 2.0 interface. Based on internet archives and technical forums, several