i found this on a site and dont believe them.
Its here! The one you have all been waiting for! We have been working on this downgrader for a long time now. It took us hours upon hours of testing and numerous bricked PSP's > to finally get this working and released.
This downgrader works similar to previous 2.0 - 1.5 downgraders, by installing an EBOOT.pbp file into the 'UPDATE' folder on your PSP which will allow you to downgrade your PSP from versions 2.0 up to 2.6, back to version 1.5 (best for running homebrew)
We haven't developed a downgrader for updates past version 2.6 yet, so dont upgrade past 2.6!
This downgrader will work for versions 2.0, 2.01, 2.5 & 2.6 only.
and heres the file
i dont wanna try this until any of u guys confirm it