Hey if you want to downgrade your psp Then I can help. If you need help feel free to post in the comments.
Now READ ON!!!

Step 1: Download Files

Okkay I just hacked my PSP cool right? Okay well you may be wondering can this work on ALL firmwares well yes it can. But you also may be thinking how does this work well it is a progam that you put on your psp and you know those old firmware updates? This thing brings them back. Soooo to the downloads. First you download this the downgrader, then you download some firmware updates.
.Downgrader:
http://downloads.pspspot.net/firmware/706-dark-alexs-time-machine-v0-1.html

Old updates:
http://pspslimhacks.com/psp-firmware/official-firmware-updates/

Now that you got that done to the next step!