Figured I'd mention that the Noobz PSP hacking team has discovered a new exploit, and probably downgrade ability that will work on (supposedly) and firmware to date. So far, it's just a 'hello world', but I'm sure they'll eventually get a HEN running on it, making it possible to run a downgrade. It runs off of an exploit found in Lumines. Lumines is a (pretty good) puzzle game that's dirt cheap, and easy to find. So if you plan on accessing homebrew, pick up a copy of lumines asap (sales of the game supposedly jumped up 14000% since the exploit was announced, don't quote me on that though, cause I don't know if it's credible), and Noobz will probably have HEN running on every single firmware through the new exploit some time soon.