Things You'll Need
Instructions
Rename the downloaded 1.5 EBOOT file to UPDATE.PBP on your computer and format your PSP's memory stick via the format option located in the PSP settings. Connect your PSP to your computer via a USB cable.
Extract Hellcats Pandora Installer and transfer the folder "pan3xx" from the "pan3xx_rev2b" folder to your memory sick at Y:\PSP\GAME. Drag and drop the UPDATE.PBP file that you renamed earlier to the memory stick, which will save it to the root. Disconnect your PSP from your computer and navigate to the Pandora Installer for 3.XX in the PSP's Game menu and select by pressing X.
You should be presented with this screen. Press R+X to go to the next screen that warns you that you are about to repartition and format the memory stick. Press L+R+X to continue with the process. This prepares your memory stick to become a magic memory stick. Once it is completed your PSP will reboot back to its home menu. Connect your PSP back to the computer via USB.
When connected to the computer, your PSP will now show up as PANDORA and will be completely blank. On the PSP, create a folder named "PSP." Inside that, create another folder named "GAME." Like you did in step 2, place the "pan3xx" folder in the "GAME" folder, and place the UPDATE.PBP back into the root of the memory stick. Disconnect from the computer.
Return to Pandora Installer for 3.xx menu and then press X to install the firmware onto the memory stick. When prompted, press L+X to install MSIPL.BIN to the memory stick. The program will exit back to the PSP's menu.
Go back to the Pandora Installer for 3.xx and press X to enter the program for the last time. Press O when presented with its menu. This will turn your inserted battery into a Pandora battery. The screen will say "Battery Pandorized" three times. Press Triangle to exit and you are finished.