My little 14 year old brother has a PSP. Why not hook the PSP up to your computer using cable, then go to my computer it will be under removeable disk (PS you have to be in USB mode on this PSP for the computer to detect it) once you detect the PSP it will be assign a drive letter and it will be under 'devices with removeable storage' (I) for example, open the removable device, by double clicking and finding the firmware file/folder next go on internet and download sony PSP firmware version 1.11 save to system then copy it or cut and paste into the PSP folder then disconnect PSP and turn it off.
next turn it on it will show the "home" section of the PSP from here you can see that the old firmware version is reinstalled.
cheers,0x0161 nice 420 in the handle.