CollegeBoard actually has a wide range of calculators it allows for the SAT (https://collegereadiness.collegeboard.org/sat/taking-the-tes...), but very few test takers take advantage of this.
TI graphing calculators are based on sufficiently old hardware that it is probably faster to emulate a TI calculator on something with the power of a Raspberry Pi. Indeed an open source third party emulator already exists (https://github.com/CE-Programming/CEmu). Does anyone know what the legality of selling a calculator that is a dedicated emulator of a TI graphing calculator (not just an online one like Desmos, but a purpose-made physical calculator that does nothing else)? I'm curious why this hasn't already been done before.
EDIT: I mean a dedicated emulator that can do nothing else but be a graphing calculator, e.g. not something on a smartphone.
I don't recommend using aides during tests.