another downgrader idea to poke at... - PSP3D.com - Sony PlayStation Portable News, Homebrew, Hacks, Reviews, Videos, Mods, Forums

slit_throats · #1 (**permalink**) 01-21-2006, 05:39 PM

everyone knows that the GTA hack cant get kernal access. well here is an idea.
from what i have read, GTA starts out using kernal mode then switches to user mode at the point your are able to start playing. now if you could run a HB that allowed you to trick the psp into exiting GTA then loading it a second time yet stopping it at the point before it switches modes you may be able to access kernal.

the key is to somewhat exit out of GTA enought to make you have to load GTA a second time while still have the HB active, so to stop GTA load proggress before it switches back to user mode.

im sure someone will say no matter how you exit out of GTA partial or fully it will exit out of the HB but it was just another idea i was sleeping on.

hbarroso · #2 (**permalink**) 01-21-2006, 05:43 PM

Yeah it´s a good idea, we should email fanjita

antonio_424 · #3 (**permalink**) 01-21-2006, 05:44 PM

Easier said than done

Sameerf · #4 (**permalink**) 01-21-2006, 05:44 PM

maybe a good idea, but how on earth are we going to pause it from switching or switch back?

Homer · #5 (**permalink**) 01-21-2006, 05:46 PM

Might work. I mean the command to quit HB and GTA (sceKernelExitGame) could be edited so it "hangs" right when it's in kernel mode.

DesertSessions · #6 (**permalink**) 01-21-2006, 05:48 PM

Would it make running homebrew easier or make it more complex?

back4orth · #7 (**permalink**) 01-21-2006, 05:51 PM

sounds good just email Fanjita about it and see what happens next.

slit_throats · #8 (**permalink**) 01-21-2006, 06:01 PM

to be honest, if this is good im sure he will see it. you guys dont need to fill up admins and fanjita's mail box with every idea that pops on a forum. if he or another hacker see's it then they can jump on it so their is no need to email anyone.

antonio_424 · #9 (**permalink**) 01-21-2006, 06:01 PM

I'm guessing it would make it more complex then it already is. If it did actually work and we were to get kernal through this, that would mean starting over, well not really, but starting from the beginning. We would still need to remake an EBOOT Loader, or an ISO Loader for any of you that want Kernal access for that (I hate pirates), but yeah, someone would need to work from the bottom up.
He would need to be a very good programmer, and be able to remake the ISO and EBOOT Loaders to work under this environment. This is assuming it works that is

.
Sounds like it might if we can get sceKernelExitGame to hang/pause right before or after it exits/enters User Mode then we might pull this off. But I'm not really sure how stable it would be and it will definately not be easy.
This is the first actual idea I've heard that is completely "New." You might be on to something, but don't get your hopes up, it might not work.
Sounds pretty ok to me though.
Now we need a programmer that knows what he is doing to pull this off or atleast tell us if it's possible.

Homer · #10 (**permalink**) 01-21-2006, 06:12 PM

I just looked at the sceKernelExitGame int and it seems like it does a syscall to address 0x20F2. Maybe if we can find the right syscall we may get access to the kernel, but I doubt it since fanjita said it was impossible to get it from GTA.
Here's the int by the way:

Code:

int sceKernelExitGame()
{
	asm("syscall 0x20F2");
}