Just to clarify, and in case it helps with debugging:
What I said here was TRUE at the time I wrote that, however several days later Firefox stopped behaving this way. Apparently Google Chrome had installed something that continued providing location information for some time after Google Chrome was removed from my system.
And after that time, Firefox stopped working in this situation. Only Google Chrome allows Google TV to provide geolocation information once more.
Good luck getting Firefox to work correctly. I'd love to remove Google Chrome again, but still want access to our local TV channels. That, or I'll soon need a divorce.