The firmware could be anything, how the TV information is displayed on the
screen.
What you need to ask yourself is, "are you ready to scrap this tv set?"
ONce the answer is yes, then it's really about how much you're willing to
spend. Since the tv set is scrap, any attempt at getting it to work is
icing on the cake. You can't hurt it since you've already decided it willb
e scrap. That gives you an edge, a willingness to take chances that you
won't if you still see hope for the set. The only other issue then is how
much you're willing to spend on a gamble.
Of course, in the internet age, it all becomes about "folk knowledge".
"Anyone" can change a board, it takes more skill and experience to at
least figure out what's wrong with the tv set. When someone can do that,
they have a better edge on replacing the board, or may be able to fix the
board itself.
But if you can only deal with plug-in solutions, then there's a very
narrow window for doing much. Get information from others, and hope it
works.
Michael