Worry about three things: 1) Is it legal. (Yes. You're making your own "rom". The only thing that will happend is that TI probably won't fix your calc cheap if it gets broken. No warranty...) 2) Can you afford it/does the price match the outcome?? 3) Can you do it?? If so, go for it. Maybe somone would port it to other calcs too. :-) Jack TK