Yo, I actually just did that today, what a coincidence. Well not sure how much firmware has to do with this but I'll just tell you what i got, cus its working perfect for me. I have 3.71 m33 update 3 firmware. Besides that, I used Simple Popstation GUI 3 Beta on my .bin of rival schools and then just took the converted file onto my psp and Bam! I'm playing rival schools on the go =D