As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF ON THE FERRY FLIGHT FROM IAH THE CREW REPORTED THAT THE LANDING GEAR HANDLE WOULD NOT MOVE TO THE UP POSITION AND A LANDING GEAR AIR/GROUND FAIL MESSAGE APPEARED ON EICAS. THE AIRCRAFT RETURNED TO IAH AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED BOTH OF THE NOSE LANDING GEAR UPLOCK PROX SWITCHES ALONG WITH BOTH OF THE NOSE LANDING GEAR DOOR PROX SWITCHES AND THE LANDING GEAR ELECTRONIC UNIT WITH NO FURTHER DEFECTS NOTED.