I've been doing a lot of reading online about the Linksys WRTU54G-TM router model that I now own. It seems getting a custom firmware onto it is not a problem. But no one is talking about retaining the Voip features (yet). So far they're all disappointed that it's not a SIP machine and used GSM over IPSec.

Personally I don't care about using it with non-t-mobile. If I take the original firmware, shouldn't I be able to extract it, and it's SquashFS image, and then move all of the t-mobile specific binaries for enabling the calling features over to a custom firmware installation (maybe OpenWRT)? You might ask why, and the reason is, that if I do this I could retain my calling features, which I do want, and ssh to the router and use it to run additional software, as any OpenWRT router could do.

Does anyone know if this can be done, and how the firmware's binaries could be gotten at and installed correctly?

Update
I have found someone working on 3rd party WRTU54G-TM firmware.
I am still interested in my second part of the questions, that is can't the stock firmware images be pulled apart and have the close-source, if any, binary kernel modules moved into another more flexible custom firmware?