Sadly, I have already tried that. Every time I load with that version, it gets to the screen where its loading the variables, freezes at 50%, and then it gives me a black screen. I was using using Revision 556 because when it freezes, I can at least return to the emulation menu and select another game. With Revision 755 (both vanilla and modded) it freezes my PSP entirely. Are there specific settings I'm supposed to run this game with? or am I screwed?
Pretty much screwed
I've tried various settings for this game and it still doesn't work. You can try World and Exotica, which I've tested and work pretty decent especially with Sync sound.
I was looking forward to USA, until it keeps freezing me endlessly, since I do have the latest Rev 755.
I'm very sorry but when new Revs do come out, you can always keep testing the game to see if any progress was made.
For the future: Check out the Compatibility list and follow the color code.