If you have purchased a PSP running Version 2.0 of the firmware, complete with browser, you can downgrade to Version 1.5 with a few easy, albeit somewhat risky, steps.
When you are done, the entire world of homebrew will be open to you.
After you have all the files in the right places, disconnect your PSP from your computer and plug it into the AC adapter.
Make sure that there is no UMD in your PSP and that you have wallpaper turned off before you begin.
On your PSP, navigate to Photo → Memory Stick and hit the X button to start scrolling down through your photos (see Figure 1-38) until you reach the file name, but if not, simply select the image and hit the X button. If your PSP freezes without going to this black text screen, hold the power button up for about 10 seconds until the PSP shuts down, then hit the power button again to start it back up. If the black screen with white text doesn’t appear to be showing up for you, try connecting your PSP to your computer again and check at the root level of your Memory Stick for a new file there called Don’t panic.
Keep in mind that working with firmware is always risky.
Having the power supply cut in the middle of a regular Sony authorized firmware upgrade could very quickly turn your 0 PSP into a 0 doorstop.
Fortunately, some industrious hackers discovered a buffer overflow error that occurs when loading an appropriately created image file through the PSP’s Photo menu.
Such an error in a normal firmware upgrade, though, would be covered under Sony’s warranty.
Anything that goes wrong with this hacked downgrade won’t be covered, so make sure you follow these steps carefully, and consider yourself warned. Also, be careful where you grab your copy of the downgrader and the 1.5 updater used in this hack; there have been reports of malicious packages posing as these two items that can actually destroy your PSP. You will also need a copy of the original 1.5 firmware update. Once you have downloaded the necessary files, unzip them.