Yo... What's the scenario? It's you, a PSP-3000 TA-095 (09g) owner, who downgraded with Davee's Chronoswitch, and cannot upgrade back to firmware 6.3x or 6.60 because you get error IDXFFFFFFFF. Anyone out there in that boat? There has gotta be a few... And this is for you: Frostegater's Physical Upgrader for said model affected by said error code.
Obtain the official 6.3x or 6.60 firmware update from Sony (we can't host OFW's anymore; copyrighted... Sony made us take 'em down) and copy that to /PSP/GAME/UPDATE/, keeping the name EBOOT.PBP. Copy Frostegater's upgrader to /PSP/GAME/Upgrader/ and launch it. That'll start the SCE updater, bringing you back to the latest and greatest, which you can later hack by installing CFW PRO or ME.