Yeah, I've heard several people say SOTN works 100%. I think that's the next game I'm going to try out.
And don't be worried about upgrading your PSP to the OE-B firmware. Mine has been at 1.5 since launch and the whole process was soooooo easy to do. Plus, you can always go back to 1.5 easily if you want. You can actually do a lot more with 3.02 OE-B anyway, like make your PSP region free for UMD movies, skip the PSP splash screens, change dashboard fonts, and a bunch of other stuff.
Here's the install package/instructions I used:
http://www.psp-hacks.com/forums/viewtopic.php?id=58272