Probably will be done in assembly but even if i just changed 1 variable to a set thing id be happy

I found one online (assembly, i wanna avoid the official app is so big) but my calc keeps crashing and it REALLY gets funky when i look at the program that i have booting on startup and almost always crashes
(All crashes lead to ram clear when starting up)

So im assuming all the breaking is from that program.
The official startup app has an offscript and a bootscript as appvars but i cant find any way to actually read those, because if those do what im looking for in a stable way that would be great because i wouldn't need to have the whole program while still having a stable bootscript, or even better have 2 programs load on startup instead of 1

Im pretty new to all this and man is it hard to find info on this stuff. So explaining any solutions you have a bit would be super helpful (mainly assembly, i have no idea about z80asm or any asm for that matter)

Im on a TI-83+ btw

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For anyone who did click on this i have a second idea

Possibly make a program that is hidden in the prgm menu? That way the user cannot run it manually only an external thing can?

_{Edit (Eeems): Merged double post}