I have 3 slim PSP 2000 and 1 phat psp 1000

currently I have 5.00 m33-6 on one of them, and 5.50 gen on the other 2 slims, and my phat still 3.71 something cfw.


I have the custom firmware that can play emulators, psx and psp iso ( latest games )... currently all my custom firmwares that i currently have keep showing my psx game as "Corrupted Files" they were just fine when i had 3.71 on them but now something isnt right .

what do you advice me to upgrade to? been gone for 2 or 3 months , and now i see 6.35 pro and stuff like that, some advice would be greatly appreciated :D