Some gateways support a hidden diagnostic page: http://192.168.18.1/cgi-bin/telnet (if enabled by carrier) – but this is rare.
Most carriers push updates in geographic waves. Connect to the gateway’s web UI (usually 192.168.12.1 ): nokia fastmile 5g gateway 3.2 firmware download
Stop searching Google for "Nokia Fastmile 3.2 firmware download." You won't find a safe, working file. Some gateways support a hidden diagnostic page: http://192