As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
OVERHEAD FLIGHT CREW REST SMOKE DETECTOR INDICATION. EMERGENCY DECLARED. FLIGHT RETURNED TO DEPARTURE. LANDING UNEVENTUL. NO VISABLE SIGNS OF SMOKE. REMOVED AND REPLACED THE SMOKE DETECTORS IN THE FORWARD OFCR AREA IAW DMC-B787-A-26-14-21-00A-720A-A. OPS CHECKED GOOD. AIRCRAFT WAS GROUNDED.