Lots of people have questions about bricked PSPs. Here is brief summary of unbricking.
Bricked PSPs These are PSPs which are completely bricked which means they are sort of useless since they can't do anything with it. Nobody likes a bricked PSP so there is a way of unbricking but is dangerous!
Unbricking PSPs If you have recently downgraded a PSP and have your NAND.BIN file backed up then its cool.
NAND: This is a file which has firmware, Flash files, Sony files, PS1 pops etc.
Back it up the next time you downgrade and store it safe somewhere on your computer.
If you PSP is bricked make a magic memory stick and put it in your memory stick. Then when your PSP boots in service mode restore the NAND. It should automatically shut off. Then boot your PSP in normal mode and it should be unbricked to the last version where you backed up your NAND.
I'm not quite sure about this =============
For people who have a bricked PSP and no NAND back up there is a risk of destroying your PSP.
NEVER RESTORE YOUR PSP WITH SOMEONE ELSES NAND. =============
Bricked PSPs may encounter error during a downgrade so it means your PSP is bricked. You must unbrick with NAND. Also, putting back NAND is a dangerous process.
NOTE: THIS IS NOT USED FOR DOWNGRADING.
Any questions just ask me. If i'm wrong correct me :)
Edit that out, so as not to confuse people, or at least say it is a VERY LAST resort, if you dont have a NAND of your own PSP and re-flashing 3.71 M33 doesn't work, but stress that it is a VERY, VERY LAST RESORT.
Editted. Just one thing I don't really get is how people actually bricked their PSPs.
I know a few ways of them getting bricked:
-While downgrading the files being coded into the PSP, The battery falls out or the PSP suddenly goes off.
-While upgrading you cancel the update halfway through.
