Get stock firmware onto a former cable company box

Hello, I have an RCN Tivo box that was found in a house we were cleaning out, I would like to use it with my local cable service (service electric cable tv & communications). Is there any way to get the RCN firmware off of this box that I have and put a stock Tivo firmware onto it and use a cablecard from my local provider?

The model number is TCD746320