Brewology

I am currently new to this and have little or no clue on firmware and i want to downgrade so i can play homebrews on my psp.
I need help on downgradeing!!
My system software is version 3.71 and the type is the FAT PSP.
Anyone help me!

You need to make a Pandora's Battery, I am not too familiar with it and have yet to make one, but there are tutorials on the site, here is one:
http://www.pspbrew.com/forum/viewtopic.php?t=9208

It's pretty easy if you know what you're doing but if you're new, it might take some time