Am...............That's not just USB collection.......but also need to format?
Have u format your psp?If not format it first(remember to put the save u want into other file.....or they'll be cancelled)......and then surely if u open usb conncetion again......there will be a file called ISO......u can put both iso and cso files into your psp......but remember that cso may lead u to go back home...........am......just depends on what gb card u're using............if u follow instruction.....i think my suggestion can help u...........