PSP Firmware help

I recently updated my PSP from 3.71 M33 to 5.00 but then i realized my games wouldn't play anymore and that i don't have recovery mode any more!
Can someone help me with my problem?
Where can i convert my PSP from Regular Firmware to Custom Firmware?
*note : I have a PSP slim

by the sounds of it youve updated from custom firmware to official firmware, youll need to get a pandora and a magic memory stick to re-downgrade the PSP.