I'm honestly surprised that groups like Pine64 haven't tried making an open source competitor.
edit: just saw a few comments down that NumWorks is basically that?
edit2: based on Phi and Omega[1][2] it looks like they no longer truly are (probably to comply with the regulation nonsense), but they still can be jailbroken.
The barrier to replacing TI isn’t hardware. Casio has cheaper calculators and test makers generally have a pretty big selection of acceptable calulators[1]. The barrier is often teachers. They don’t want to change from what they know already.
edit: just saw a few comments down that NumWorks is basically that?
edit2: based on Phi and Omega[1][2] it looks like they no longer truly are (probably to comply with the regulation nonsense), but they still can be jailbroken.
[0] https://www.numworks.com/
[1] https://phi.getomega.dev/
[2] https://getomega.dev/