As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF CREW EXPERIENCED FLAP POWER FAIL. DECLARED EMERGENCY AND RETURNED TO BOS. THE FLIGHT LANDED WITHOUT FURTHER INCIDENT. DUTY OFFICER HAS CONTACTED FAA REGARDING THIS FLIGHT. CLEARED ECU CONTINUES BIT FAULT FROM CDS IAW Q400 MM 15-00-27. PERFORMED OPS CHECK OF FLAPS SYSTEM IAW 27-50-00. OPS CHECKED GOOD.