How to...

How to install 3.90M33-3 on a PSP slim

Requirements
PSPslim with M33 firmware 3.60-3.80
Battery 100%

First, go to dark-alex's website to download 3.90m33-3.download the orginal 3.90 Sony Eboot from psp-hacks, extract the orginal eboot and rename it as 3.90.PBP. plase it inside the 3.90m33-3 folder that you downloaded from dark-alex's website.

Lastly, place the entire folder inside PSP/Game Not ISO and run it from the XMB

PSP with orginal firmware should not try this. Recommed to have 100% battery
Do it at your own risk, i will not be responsible to anything that happen to your PSP.