Not To Sound any n00bish but
i ran 2.80 update i changed everything in the eboot
to 3.00 and it worked i got version 3.00
i did it on a psp 2.80 ta-082 motherboard
i was mad for a second but it worked
it didn't say The File Was corrupted or anything
my psp version is 3.00 i changed it everything from 2.80 is still on it