If you have Official firmware 3.5 or above the ONLY way you can get to custom firmware is with a Pandora battery. However it takes a Custom Firmware PSP and a Windows XP computer to make one, but you can get one off of ebay and then you can easily AND RISK FREE put custom firmware on your PSP. The most Current PSP Custom Firmware out is 4.05m33 by: (the famous) Dark_Alex. AND Also you can go from 4.05 m33 back to official firmware anytime you want too.