J'ai peut être un espoir...
J'ai trouvé ça sur Wololo
" I had the same problem a couple days ago but I fixed it.
First what you need is a memory stick. If you have one then download this recovery menu http://www.mediafire.com/?kzxocs9mxgvb95k
and put it in the root of your memory stick. It should look like ms0:/recovery.prx
After you have the recovery menu, take out your battery, and restart your PSP while holding the R shoulder button. Then press toggle usb and you should have access to your memory stick. What you need to do next is make a folder in your GAME folder called RECOVERY.
Now download PSPFiler 6.6 and put the eboot.pbp in your RECOVERY folder. Then toggle usb off on your PSP and select Run ms0:/PSP/GAME/RECOVERY/EBOOT.PBP
It should load up a screen asking you for a language, choose English and it will show a menu of your memory stick folders and files. Press the start button until it says FLASH1 on the top left. Then press R shoulder + L Shoulder + Left button on DPAD at the same time for it to say HACKER MODE.
Once you have that, open the registry folder in the flash1 and delete system.ireg and system.dreg files. DO NOT DELETE THE FOLDER ONLY THOSE 2 FILES. Then what you should do is press Home button and exit PSPFiler. It should load up the default settings screen and you have to enter the basic info again