First, plug in the PSP and make sure that it’s fully charged.
This is vital because you’ll be screwing with the firmware on the device, and losing power and shutting down during a firmware flash is one of the quickest ways to brick your precious handheld.
In this page I’m describing the easiest possible way for you to install the most reliable Custom Firmware on your PSP: Pro CFW.
As a PSP 1000 owner, you can practically install everything you want on your device, and use other techniques such as the Pandora Battery to install a Custom Firmware.
To install the 6.60 Firmware, just unzip the archive on your PSP’s memory stick, in the “PSP” folder (you should end up with an “UPDATE” folder in the PSP folder, if you do things correctly), then run the update from your PSP menu. Ask for help on our forums The Pro CFW archive provides several subfolders in the “PSP/GAME” folder.