As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT DIVERTED TO BNA AND LANDED WITHOUT INCIDENT DUE TO PERSISTENT ROTTEN EGG SMELL IN THE MID TO AFT CABIN. FUMES LINGERED AFTER BOTH PACKS WERE OFF AND RAM AIR OPEN. CREW REPORTED PHYSICAL SYMPTOMS DUE TO ODOR. MAINTENANCE TROUBLESHOT TO OVER-SERVICED APU. CLEANED APU LOAD COMPRESSOR, PERFORMED ECS DECONTAMINATION AND REPLACED HEPA FILTERS.