Hello from Maine,
I just took a "crash course" in PSP hacking.
I had to downgrade my daughter's PSP from 3.11 to 1.50, then apply custom firmware 3.52-4 and figure out how to play ISOs.I took notes in case I would have to do it again in the future.
I've uploaded my notes and all software i used here:
http://tinyurl.com/6flkoqIt is entirely self contained, you will not need to download anything else. I also simplified the instructions - it is so easy a monkey could do it.
Maybe it could save you hours of Googling and the risk of reading outdated tutorials.
You will need the game "Lumines" to do this method.
I got "Lumines" from GameStop for $34. They are on ePay as well.
Dig it?
Craig
EDIT : I have updated the above (April 2008). Now the pack does this:
1. Any firmware less than 3.51 to 1.50
2. 1.50 to 3.52 M33
3. 3.52 M33 to 3.90 M33-2
I have tested this exact software pack on 3 different PSPs and was 100% successful in hacking them.