As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB FROM BOS THE CREW REPORTED LAV SMOKE AND BAGG SMOKE EICAS MESSAGES FOLLOWED BY SMOKE IN THE CABIN AND COCKPIT AT 3,000FT. THE QRH WAS FOLLOWED AND THE CREW DECLARED AN EMERGENCY AND RETURNED TO BOS. DURING APPROACH THE INDICATIONS CLEARED AND THE AIRCRAFT THEN LANDED WITHOUT INCIDENT. MAINTENANCE PERFORMED ENGINE OPS CHECKS AND BLEED CHECKS IAW RR FIM 72-00-00. OPS CHECKS WERE GOOD WITH NO DEFECTS NOTED. AIRCRAFT HAD BEEN DE-ICED PRIOR TO DEPARTURE.