Hi guys, i have a problem with upgrading my psp.

I have a psp slim (psp 2000) with a motherboard of TA-85, so it's hackable.
Currently, my psp is running on firmware 4.01 M33-2.
I have a pandora battery as well as a magic memory stick.
I also have another spare memory stick which i tried to make it into mss with 5.00 custom firmware.

I followed alot of tutorials out there. But whenever i hold the L trigger and pop the pandora battery in, it's just black screen with green light.

I know its brick and so, i unbrick it using my 4.01 mms.

Any idea what went wrong? '
I tried using Rainmms, pspgrader etc but none of them helps me to upgrade to 5.00.

I want to play the newest game out there, and from 4.01m33-2, which version should i upgrade to?