Originally Posted by Dave_S
There is no need to run the provider's firmware if you have something better. XDA-Developers has has a tremendous amount of firmware to choose from for a variety of current smartphones.
The FCC has severely frowned upon that sort of activity. Comcast
I'm sure they can contrive some way to make a locked down system, with hardware encrypted phones running an OS that only barely qualifies as Android if they really wanted to. There is no FCC rule about requiring open device access to cellular nets as far as I know.
The point is, we're both saying yes, you can run a wifi hot spot on your Android phone without paying extra for the privilege. (Though you might end up paying extra for the increased data usage.)
I'm just not going to swear that there isn't SOME provider out there with some handsets that have effectively blocked it. I don't know them all.