As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - CREW REPORTED FORWARD CARGO DOOR EICAS MESSAGE IN FLIGHT. EMERGENCY DECLARED FLIGHT RETURNED BOS LANDED WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. DEFERRED FORWARD CARGO DOOR ELECTRICAL DRIVE INOPERATIVE PER MEL. REPLACED GROUND SERVICE BUSS TRANSFORMER RECTIFIER UNIT AND LOCK SENSOR AT MIA ON 03/17/2012. SYSTEM GROUND CHECK NORMAL OPERATION.