As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED A LAV SMOKE WARNING ION EICAS AFTER TAKEOFF. THE CREW PERFORMED QRH WITH NO SMOKE NOTED. THE ACFT LANDED WITHOUT INCIDENT WHERE MX REMOVED AND REPLACED THE LAV SMOKE DETECTOR PANEL, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.