Alors en me baladant un peu sur le net j'ai trouver quelqu'un qui a trouver une facon de downgrader....
et au vu des commentaire il y a plusieurs personnes chez qui ca a marcher !!

PS : je ne prends aucune responsabilité d'un quelconque dommage sur la console.

"Ok here's what I did, I have a 1.51 PSP from Europe and it comes with a UMD that has the 2.0 firmware on it. So I put in the disc and started the upgrade, and at the point where it said "make sure the PSP is pluged into an AC adaptor" or something like that I can't remember it word for word. It is the last point at which you can cancel the upgrade. Anyway before I continued I removed the disc and inserted the Midnight Club 3 disc and then continued. Being that it had already bypassed the version check it continued to load the firmware thinking that it was the 2.0. Now I know that this works because I tried it on three of my friends PSPs all 1.51 I tried it on mine first so I wouldn't brick theirs. And all of us can run homebrew cool! I am guessing that this will only work on 1.5x versions seeing as how you can't use the 2.0 disc to upgrade one with 2.0 already on it. I hope someone will find this helpfull."


En clair il dit que il lance le UPGRADE en 2.00, il y a un message qui dit : Verifiez bien que la console est branché sur le secteur :, a ce moment la il a mi le jeu MIDNIGHT CLUB 3!
Sois disant que la console a verifier AVANT quelle version de firmware il allait installer...!

Je sais pas mais... de ce que j'ai vu sur les commentaires plusieurs personnes disent avoir réussi !!!

Que quelqu'un essai et nous donne des nouvelles !