I'm an owner of several Casio calculators, all from the fx-82MS series. In Spain (where I live) they are very common because they are really cheap.
So, I wanted to hack it of course. I already have experience in reverse engineering and exploit development (https://github.com/pedro-javierf/). Nevertheless the calculator scenario is much more complex, at least for the casio fx-82ms which isn't programable.
So far I know there's this software glitch (sometimes called overflow but I don't really know if it's a classic stack overflow or someone just gave it the name):
which basically unlocks every mode from the superior model (fx-82ES I think?) on this 10eur calculator (though not all of them are really usable)
This is patched in the newer model, which (when turning off) prints the casio logo.
Also, the hardware is completely different. I'll post some images in the following days from the newer model, but a Spanish colleague already reversed the hardware for the old model: http://nitehack.blog...k-incluido.html
the most interesting thing is that he found that the hardware beneath the buttons is in fact a matrix keyboard. There are more pins (keyboard combinations) that were actual buttons in the calculator, so he analyzed that and found that some combinations can be triggered to directly activate extra modes from the superior model. I have a hardware setup for that I'll show off as soon as possible. The software layer is still pretty much unexplored, so that's why I'm here
I've seen you people have done a lot of research into better, newer and more complex models (even ROP chains If I'm not wrong!) which is amazing. How could I apply some of that knowledge to reverse the fx-82MS? I've read something about official casio emulators?
PS: Since I don't have any newer model I can't really help, but I will try if y'all need something