pspandnfsfan

downgrade psp 6.20, 6.10 and 6.00 ofw firmware

Install 5.50Gen-b on any psp - Downgrade 6.10

downgrade any 5 02, 5 50 and 5 51 psp to custom firmware

downgrade 5.50 and 5.51 to 5.00 m33 (to play free psp games)