Use a tool like WinRAR or 7-Zip to extract the contents of the pandora (3).rar archive. Prepare Memory Stick: Connect your PSP to your PC via USB in USB Mode . Backup any data on the Memory Stick Pro Duo to your PC.
Do not proceed without backing up your memory stick.
Download the official PSP Firmware 1.50 or custom firmware (like Dark_AleX's). Rename the firmware file to UPDATE.PBP .
Copy it to the root of your memory stick (where the PSP folder is). Insert the "Magic" memory stick into the PSP. Insert a Pandora-modified battery. The PSP should boot into a menu automatically. Press the button (usually X) to flash the new firmware. Important Safety Tips
This method does not work on PSP-3000, PSP Go, or E1000 models. To give you the most accurate help, could you let me know: Are you trying to unbrick a PSP or install custom firmware ?
Requires a compatible PSP (PSP-1000 or some 2000 models) and a specially modified battery. How to Use the pandora (3).rar File
It is a soft-modding tool that allows a PSP to enter a special Service Mode, ignoring corrupt flash memory (bricked state) and enabling custom firmware installation.
What is the of your PSP (found on the bottom or under the battery)? Are you using a PSP-1000/2000 or a later model?