[GUIDE] Unbrick a PSP Slim or Classic.
This guide will show you how to unbrick your bricked PSP Slim, or bricked PSP Classic
Feedback is appreciated
What do I need?A PSP you wish to unbrick; PSP Classic, or PSP Slim.A PSP with a Custom Firmware.
ORA PSP with Official Firmware 1.50.A USB Cable.The unbricking files (Version 3):
Via Dark-Alex.org.Via Sendspace.Via Rapidshare.Via File Factory.Via Files Host.
If you already have a Pandora Memory Stick (Or 'Magic Mem Stick') then you can skip the following steps. If not, carry on:
Format your memory stick via Settings > System Settings > Format Memory Stick.
Now use the mspformat.exe found in the Pandora installation files to partition the memory stick. The instructions on running the mspformat.exe can be found here.Remove your USB cable from the PSP. Take out your memory stick.Place your memory stick back in the PSP, and connect to your PC via USB cable.You must do these steps, whether or not you already have a Pandora Memory Stick.On your memory stick, create a folder named 'PSP'. In that folder create another folder named 'GAME'.Copy the folder found in the unbricking files named 'despertar_cementerio' to 'X:/PSP/GAME/'.Download the 1.50, 3.40, and 3.71 EBOOT's.Rename each eboot.pbp to the following:
1.50 eboot.pbp -> 150.PBP3.40 eboot.pbp -> 340.PBP3.71 eboot.pbp -> 371.PBPPlace the newly named eboots in the root of your memory stick.If you are on a custom firmware:
Turn off your PSP completely.Turn your PSP on holding the R button.Go to Configuration > Game Folder Kernel.Press X until the 'Game Folder Kernel' becomes the version of your custom firmware. For example, if you had 3.03OE, then set it to 3.03.Run the application from GAME > Memory Stick, in the XMB (PSP Main Menu).Once it has finished you will have a file named 'msipl.bin' in the root of your memory stick. If you already have a Pandora Mem Stick, skip this step. If not, use the msinst.exe found here to install the ipl onto the memory stick.You can now delete the two files named 340.PBP and 150.PBP.You have completed this section. All you now need is a Pandora PSP battery, if you haven't already made one. Please continue to the next step.
Unbrick your PSPPlace your memory stick in your PSP, and your battery. In that order.Your PSP will turn on automatically.Your options are:
Press X to install 3.71M33-2.
On a PSP Slim, you will see the orange led flashing. This means that 371.PBP is being written to your flash0. When finished, both the orange and green led's will flash.
On a PSP Classic, you will have to press X when the installation is finished (you will be told when on-screen).Press O to install the official 3.71.
The rest of the process is exactly the same as the X option (installation 3.71M33).Press  to dump your nand to nand-dump.bin.
When done, your PSP will automatically shutdown.Press L+R+HOME+start to restore your previously dumped nand from nand-dump.bin
Only choose this option as a last resort. It is very dangerous. If you use a dump that is not yours, your PSP will definitely brick. The dump must be yours.