Ok now I don't know what it was exactly that made it downgrade, but all the sudden it just did.
I was just sitting here, doing noting, happen to be sitting right in the middle of this symbol
there happened to be a GTA LCS EU version, a death human foetus, the head of a pink spotted toad, a pair of baby seal eyes and a ham sandwich spreaded over the 5points of the symbol.
at the same time I happened to be covered with the blood of a freshly slaughtered goat with a burning black candle on my head while reciting the lyrics to the Afghan anthem backwards.
and i swear to god, afther reciting those lyrics backward I took a bite out of the ham sandwich and POOF, my PSP was downgraded, i swear to god, this is ****ing great.
I don't know what exactly downgraded my psp, but I think it's worth a try for everyone, just try it out and let us know if it worked out for you.