Hackers have found a new way to run homebrew applications on the PSP despite the introduction of firmware version 2.5, according to a post on PSP3d.com.
Sony introduced the firmware upgrade after hackers cracked version 2.0, which gave the PSP a web browser, and found a way to downgrade it to version 1.5. Now, thanks to stuff to do with EBOOT, TIF patches and other things we don't really understand, word is that 2.5 has been cracked too.
We haven't seen it in action so we can't tell you if it works for sure - and do bear in mind that there have been cases of viruses masquerading as handheld hacks floating round the Internet before.
It's also worth mentioning that Sony takes a strong stand on the issue of firmware hacks and homebrew applications. If you install something which mucks up your PSP, you'll get no sympathy from them - and certainly no offer of a replacement machine. Don't come crying to us, either, because we're too busy trying to make our Xbox 360 access Teletext.