As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5477- DURING CLIMB-OUT OF BOS RECEIVED AN ANTI-ICE DUCT WARNING MESSAGE. CREW DECLARED AN EMERGENCY AND RETURNED TO THE FIELD. PERFORMED A FUNCTIONAL TEST OF THE CONTROL SENSORS AND AN OPERATIONAL TEST OF THE WING ANTI-ICE CONTROL AND INDICATING SYSTEM. UNABLE TO DUPLICATE DISCREPANCY.