Okay, so my little brother had custom firmware on his PSP. But he updated the firmware the other day from the PlayStation website. He's up to 5.51 now. None of the CSO files I downloaded show up on his PSP but they show up on mine. Is his custom firmware gone now? Is there anyway I can downgrade it to get him to 5.00? He also needs the M33 menu, which doesn't show up on his PSP now. Can I downgrade it for him without the magic memory stick or Pandora battery? Thanks.