I think he's planning to use some inline ASM in there too. Regardless, he should test on emulators first, in case, and if he's planning to use it for what I think, then first, he really needs to make sure the user won't be able to access the certificate stuff and that the rest of the non-RAM stuff appears to the user only in read-only state (in the program). For what he wants to do (providing this is what me and Quigibo are thinking about), he will really need to be certain his If condition logic operations really works perfectly before loading anything on his calc, so he won't accidentally go out of bounds then cause nasty stuff.

Interesting, i cant wait to see what this is for.  Although i am a bit worried that something bad might happen make sure to test all your code on an emulator!  Or else calc bricking might occur....

It uses a absolute calling, so you can't have a pure hex version unless you know the exact address this code is going to be inserted.