i've got my hands on an factory unlocked italian 3g iPhone (MB496T) and for some reasons the phone part isn't working.
what I really can't understand is this: as I insert the SIM card I can actually get the carrier logo and 3G connection but it wont get any signal bars...
I can't make a phone call at all but, on the other hand, I can surf the net without problems...

this is something beyond my knowledge... hardware issue? any hint?
(it is upgraded to 3.1.2 with a 5.11.07 baseband; restored, donwgraded and reupgraded countless times...)