As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MSP INFLIGHT - CREW REPORTED HEARING LOUD BANG IN AFT CABIN FOLLOWED BY FLIGHT ATTENDANTS REPORTING SMOKE IN CABIN AND AFT CARGO FIRE WARNING INDICATION. CREW DISCHARGED CARGO FIRE SYSTEM. RETURNED TO MSP AND LANDED WITHOUT INCIDENT. REPLACED BLOWN WING ANTI ICE DUCT IN AFT CARGO COMPARTMENT AND BOTH CARGO FIRE BOTTLES. SYSTEM GROUND CHECKED NORMAL OPERATION.