As of today there is an exploit for all US PSP version 1.50s. Before only japanese 1.0 worked. Last week they released a way to play unsigned code using 2 memory cards, this week they have it down to 1. So I have been playing some TG16 and SNES on the old PSP today =). And what was the first thing I had to do, well make a Berserk wallpaper for my PSP lol.