As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 2066 - RIC - FLIGHT CREW REPORTED AIR GROUND FAIL INDICATION ON EICAS DURING CLIMBING. FLIGHT CREW PROCEEDED WITH AIR RETURN AND LANDED ACFT WITHOUT ANY INCIDENTS. RIC MX REMOVED AND REPLACED NOSE LANDING GEAR UPLOCK PROXIMITY SWITCH AND PERFORMED OPERATIONAL CHECK SUCCESSFULLY. ACFT WAS APPROVED TO RETURN TO SERVICE.