I know it's been a while, but I had been wondering if the Pro CFW team have ever addressed this problem. Namely, with PRO C2 CFW, I can't launch any PSX games at all. Admittedly, I hadn't tried just a straight PS1 ISO, but I've made the point of trying to re-pack (where applicable) or use a PSN flavored version of a PS1 game I would like to play, and last I tried, none of them worked at all, giving me a FFFFFFFF error and exiting out. It didn't matter if I made or packed the ISO myself. It's only particularly distressing because the official Google Code page won't provide a download link to Pro C, which was the last build that worked correctly with all the games concerned.