As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING AIRCRAFT CLIMB OUT, RT PACK FAILED EICAS MESSAGE ANNUNCIATED IMMEDIATELY FOLLOWED BY SMOKE IN THE CABIN. FLIGHT CREW FOLLOWED EMERGENCY CHECKLIST PROCEDURES AND RETURNED TO DEPARTURE AIRPORT. REPLACED THE RT AIR CYCLE MACHINE IAW AMM 21-52-01.