As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2050 - RIC - FLIGHT CREW REPORTED "LAV SMOKE" ON EICAS WITH ALARM, BUT NO SMOKE OR ODOR NOTICED. ALARM WENT AWAY AFTER ABOUT 1 MINUTE. RIC MX INSPECTED WIRING FOR SYSTEM AND CHECKED GOOD. MX REMOVED AND REPLACED SMOKE DETECTION PANEL AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. ACFT WAS APPROVED TO RETURN TO SERVICE.