As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 4189 THE CREW REPORTED AN ENGINE ONE FIRE DET FAIL MESSAGE ON EICAS DURING CLIMB AND DESCENT. THE AIRCRAFT LANDED IN JAN WITHOUT INCIDENT WHERE MAINTENANCE REMOVED AND REPLACED THE NR 1 ENGINE FIRE DETECTOR HARNESS, OPERATIONALLY TESTED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.