Endless Paradigm

I really don't like bothering you guys for help on the PSP but right now I'm feeling helpless.
Okay so I was using 6.39ME but then my friend wanted to play duodecim. My save file wouldn't work and I tried to repair it to work with my firmware but it still wouldn't work so I decided to go back to 5.00 M33 to get it to work.

I tried using a pandora battery to do it but now my PSP is bricked and I don't know what I should do. Thankfully I do have access to someone else's PSP if I need one working.

Thanks.

EDIT: Whoops, for some reason I forgot that RSOD means bricked and BSOD isn't that harmful. I forgot to press O.
Although now tht battery I used is fudgeed :/

Can't get into recovery via the battery?
What happened to the battery?

Yea what zinga said.... A pandory battery is designed to bail you out of a brick.

Just but your magic memory stick in, choose 5.00m33 if that's what's on it, and your all good.