As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: NOSE GEAR WOULD NOT RETRACT AFTER TAKEOFF. AIRCRAFT RETURNED TO BOS WHERE IT LANDED SAFELY WITHOUT FURTHER INCIDENT. NOTE: NO EMERGENCY WAS DECLARED. MAINTENANCE FOUND THE NOSE GEAR GROUND LOCK PIN INSTALLED AND REMOVED IT PER AMM 32-00-00.