PSP Hacks, PSP Go Hacks, News, and Info. Find out about PSP Hacks and tricks such as: Converting video to PSP format. Running homebrew software. Compile PSP Linux. PSP Home Control. PSP Swap Trick. PSP Web Browsers. PSP WiFi Functionality. PSP controlled car
Someone has used the previously mentioned tools to extract a 1.0 firmware form their PSP. I'm not sure how useful it is. While it's good to have the files for exploration, most of them are encrypted and useless.
Besides that, there is no known way to package these files into a valid 'firmware updater' program to downgrade a PSP.
Some people are experimenting with the 1.50 and 1.51 to see if a downgrade process is even possible. What really sucks is that now that Sony will be putting firmware on the UMD disks, and requiring an update to play the game, it really hurts when a new game comes out and you have to lose all of your hacks and homebrew software to play it. At least until someone cracks the new version of firmware.
I see a long battle ahead. Best of luck to the programmers! Ps2Dev.org seems to be making the best progress out of all of the sites I've visited.