Patching sceKernelExitGame

[Pirata Nervo]

My program patches the function sceKernelExitGame(), it's replaced with my own function which restarts my application.
What function do games use to exit? is it sceKernelExitGame? When I run ISOs or UMD's from my application, the function is lost, do I need to do what the NOKXPLOIT app does?
"The patch will remain resident in the firmware until one of these conditions happen:

1) A program crashes the psp, forcing you to do 2.

2) You restart your psp holding the power button or remove the battery. "

any help would be appreciated.

Edit:
The function sceKernelExitGame is replaced now with my one but it crashes, I am learning MIPS again so I can understand the bootstrap better.