Here is an easy to read guide on how to downgrade your 1.50 psp to the 1.00 frimware.
Written by me Hacker3.0
Guide to complete success of the downgrader--
1. reset to default settings and format memory stick and make sure you don't have any custom fonts, sounds, wallpapers, or anything *** you do not have to reset to default settings but it i an added saftey precaution ***
2. then go to psp-hacks.com and click downloads firmwares then the 1.00 downgrade helper files and put that folder in the root of your memory stick
3. Download 1.50 -> 1.00 downgrade form the
psp-hacks front page or below the 1.00 downgrade helper files in the downloads section of
psp-hacks and put the %__SCE__downdater100 and __SCE__downdater100 folders in the game section of your memory stick
4. download the 1.50 update from
here: http://dl.qj.net/dl.php?fid=163 and put it in the mso:/PSP/GAME/UPDATE/ section of your memory stick
5. run the downgrader from the GAME section of your memory stick ***make sure you have the 1.50 update in MSO:/PSP/GAME/UPDATE section of your memory stick***
6. after you load the downgrader click x when it asks you to and let it flash all of the files.
7.Then near the top of your screen after 2-3 minutes it should say something like do a manual reboot of you psp to finish the downgrade.
well there you have it how to downgrader you 1.50 psp to 1.00
the password to get in tothe archive is: I_Use_It_At_My_Own_Risk
-Hacker3.0