***IMPORTANT NOTE***If you encounter an error that says "There is no need to update, a later version of the system software is already installed." Download this file: Open the Archive you downloaded, connect your PSP to your computer.
Open the PSP folder on your PSP, and then the GAME folder.
Don’t panic, if this is the case, the downgrader will let you know.
If this happens to you, then your only solution is to 🙂Important Note: Some recent PSP Motherboards (7g and 9g) cannot be downgraded with this tool.
DOWNLOADS PAGE: As you will notice, the downloads are DIFFERENT for the PSP Go.
This is useful for installing custom firmware of a certain version.Update: Part two, for firmware 3.51 and higher is now . Due to this (and probably some other reasons as well), Sony has been trying to repress homebrew as much as possible.Or better download the complete up-to-date PSP Downgrading/Upgrading Guide now in PDF. Where these applications could initially be run on the 1.50 firmware PSPs, users who updated wouldn’t be so fortunate.For instance, if your PSP is version 6.60 and you want to install 6.20 PRO you can use this to downgrade.**IMPORTANT**Your PSP may only be lowered to the firmware that it was SHIPPED WITH. In the video, I go from 6.60 to 6.20, but it is possible to go to any other firmware that your PSP can support.Much props :)***END IMPORTANT NOTE***So that is about it.