i have a new slim psp 3.90 and i want to put custom firmware 3.90 m33 but it says i already have the latest version do i need to downgrade my psp to an earlier version? plz respond ive been trying to do this for weeks lol
You can't simply upgrade to 3.90 M33 through normal means... you need a Pandora battery and magic memory stick. Check this thread for more information:
http://forums.exophase.com/showthread.php?t=6832