I am trying to setup my old beetel 450TC1 as wireless repeater for that i need to do firmware upgrade so that the WDS option will come in that. But the modem's firmware is refusing updates.

The specs are

Modem :- beetel 450TC1

RAS version: V85.2.04.02__TWD-ZZ-002

Any ideas ? I have already tried TM4-0Q-008,16,20 and 25 none of them are being accepted.