As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMBOUT OF BDL AIRCREW GOT AN APU FIRE WARNING EICAS MESSAGE. AIRCREW DECLARED AN EMERGENCY AND RETURNED TO BDL WITHOUT AN INCIDENT. MAINTENANCE INSPECTED AND FOUND NO INDICATION OF FIRE. THE APU WAS DEFERRED DUE TO ERRONEOUS FIRE WARNING MESSAGE AND THE APU FIRE WARNING SYSTEM WAS ALSO DEFERRED.