PSP Factory Reset

noob question.. from a noob... for all the noob's that have been wondering...

does anyone konw how to factory reset the PSP? i'm not talking about the "reset default settings" option, but a true factory reset. you know, like the xbox ones that vary according to the serial number of the console. the kind of thing that would restore a system from the leaked firmware upgrade, for example.

i only ask, as i assume many others have (however i can't find any relevant threads) because this would presumably also reset the bios to 1.0. am i wildly off the mark? after the bios has been updated, is there no theoretical way of reverting it back? please, oh wise ones, clear this up for the rest of us... the unwashed

oh well, after a bit of hardcore googleling (if there is such a thing) i've gleamed that there is probably no (easy) way for me to do what i want. so i think i'll steer this thread in a different direction:

1) any coders/ knowlegable people care to explain to us noobs, why we can't revert back to previous BIOS' (possibly even explaining what these whole bio's thingies are?!.... i understand really ;)

2) a venting of my (and probably other forum members') frustration at having rashly installed the 1.5 update. damn it! if only i'd checked out the psp homebrew scene a little sooner! strange isn't it, how quickly it's developed. i'm looking forward to the next few months/ years seeing what the community can come up with.

ps: sorry for double posting, i know it's a faux pas on most forums, but i've had a bottle of wine so i don't really give a fluck.

As far as I am aware there is no way to reset to version 1.0.