This downgrader fools the PSP by pretending version 2.5.
Instructions;
Create a folder for the update data on the Memory Stick.
Download the update data and save it in the "UPDATE" folder
Location: Save in the "UPDATE" folder
Filename: Save as filename "EBOOT.PBP"
Update procedure
Notices
Before starting the update, you must do the following:
Check that the battery is fully charged.
Connect the AC adaptor to the PSP™ system and plug it into an electrical outlet.
During the update:
Do not remove the AC adaptor.
Do not turn off the system or remove the Memory Stick Duo™ media.
If an update is canceled before completion, the system software may be damaged, requiring servicing to repair or exchange.
After it’s done, if you want restore 1.50 firmware use the MPH Downgrader.
If you want the files to downgrade reply to this Thread and i will send the files to your e-mail