for NBN connections. Its defining feature is a built-in 4G LTE backup, which uses a pre-installed SIM card to maintain internet connectivity if the primary fixed-line service fails. Firmware Management and Updates
Source and authenticity: Only use firmware from verified vendor or ISP channels. Verify checksums or digital signatures when available to avoid malicious or corrupted images. sagemcom f-st 5366 lte firmware
To check which firmware your unit runs: