You're best bet is to wait for the downgrader, but as the others have said one has not been released and one may never be released.
QUOTE(moere77 @ May 26 2007, 06:10 PM)

u guys are verry lucky im on 3.40 en i think ill go for a new psp with low fw and thank all u for the help and usefull hints!
xD I'll trade you my PSP FW 3.11, for your 3.40, my PSP was on CFW for A LONG TIME, and now I am forced to be on offical FW.