I recently got a TI-83 Plus, and am considering learning to develop and hack it (I read that you can overclock it and add accessories). However, after I downloaded TILP, I noticed a little notice that came up:

ROM contents is copyrighted by Texas Instruments. You are not allowed to copy and/or distribute any ROM image! For more informations, see the License Agreement provided with any FLASH OS upgrade.
As a lover of free software (I could be Richard Stallman's clone), this really bothered me, as I was going to be using this calculator in Algebra. I also was bothered by the fact that there was little mention of any controversy about the ROM being copyrighted. As I am considering learning to program for this device, I'd really like your input on this. I don't want to develop software for a proprietary operating system, however, with all of the hacks and massive userbase for this device, I find it hard to consider not learning to program for it. Is there some kind of open source operating system that I can install on it, or will I be forced to submit before the evil wrath of proprietary software.
Since everyone in my class will have the TI-84 (I believe it is compatible), any applications that I make would run on my friends' calculators, which would be pretty neat.