Downgrade firmware 3.52?

Hey welcome to the site. Well the 3.52 downgrader would be the 'Pandora's Battery and Magic Memory stick' There are plenty of tutorials that teach how to make the battery and there are several methods of doing different things. However, making the Pandora's Battery and Magic Memory does require another psp with custom firmware, since the Pandora installer is a homebrew app and only custom firmware can run homebrew apps. (or 1.50) So if you know anyone with custom firmware, you can get them to make you the battery and memory stick.

There IS a tutorial of how to make the battery by opening your battery up and soldering a pin, but there is a chance you might break your battery. And you can make the memory stick files yourself using this tutorial http://forums.afterdawn.com/thread_view.cfm/591203

Here are some tutorials about making the pandora's battery and the special memory stick
http://pspbrew.com/forum/viewtopic.php?t=9208
http://pspbrew.com/forum/viewtopic.php?t=10454
http://pspbrew.com/forum/viewtopic.php?t=10137
http://pspbrew.com/forum/viewtopic.php?t=9572

Take a look at those and see which one you would like to use.