As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS - FLT 4649 - DURING TAXI FROM GATE, CREW REPORTED A NR 1 PITCH TRIM FAIL. AIRCRAFT WAS RETURNED TO THE GATE. MAINTENANCE REMOVED AND REPLACED THE HORIZONTAL STABILIZER CONTROL UNIT IAW EMB MM. OPS CHECK WAS GOOD AND AIRCRAFT WAS RETURNED TO SERVICE. (M)