As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT RETURNED TO THE FIELD. CREW REPORTED A DU1 OVERHEAT MESSAGE AND SPS ADVANCE MESSAGE WITH STRONG ELECTRICAL SMOKE ODOR IN THE FLIGHT DECK AND CABIN. MAINTENANCE FOUND THE DAU 1 BAD AND REPLACED IT AND PERFORMED THE SYSTEM OPERATIONAL CHECKS.