Are you looking to or are you trying to update the router to fix a connectivity issue?
The is an older ADSL2+ modem/router (802.11b/g, 4-port Ethernet, 1 RJ11 for DSL). It was widely deployed by ISPs in emerging markets (e.g., BSNL India, Oi Brazil, various African and Southeast Asian carriers). Firmware is heavily customized per ISP, making generic updates rare.