This thread is a week old, but if you still need help, well here it is.
There's a complete walkthrough that helped me with my PSP, but you need the following if you want any chance at being able to mod it:
- An unpatched version of GTA:LCS
- Hot Shots Golf 2 Data Files (I have the files, so if you want them I can give them to you.)
- A PSP that hasn't been upgraded to 3.10 or higher firmware.
Here's the link to the guide: Downgrading PSP (
http://www.pspiso.com/index.php?topic=7615.0)
Hope this helped! =)