Title says it all. I have a UMD disc of The Simpsons Game (crappy, I know, got it from my friend). It used to work when my PSP was still on 5.00 M33, but I recently figured out that, after upgrading to GEN-D3, it doesn't work anymore and after showing the Sony splash screen, the screen just turns black and stays that way. I can, however, still use the Home button (or whatever that return-to-menu thing is called) so it's not like the game freezes or anything. I don't really need the game to work again as to say, but it would be nice to have all my discs working again (all others work, only this one doesn't). After having a look around on the internet, I found that some other people were having problems with one of their UMD's no longer working with GEN-D3 installed, but they said the UMD's still worked when they had GEN-B(2) installed. So, now I was wondering whether it would be possible to downgrade from GEN-D3 to GEN-B(2), because I want to keep the GEN firmware (it's much easier to use than M33 IMHO). If it is possible, teach me the ways, because I wouldn't want to end up with a bricked PSP (I know some bricks can be fixed, but not all, so I'm a little wary).