As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AFTER TAKEOFF FROM MIAMI LOST BOTH FLIGHT DIRECTORS. THEY CAME BACK WHEN LNAV RE-ENGAGED. WHEN ATTEMPTING APPROACH TO BOSTON, BOTH FLIGHT DIRECTORS FAILED. FLIGHT DIVERTED TO PVG, LANDING SAFELY. REPLACED FLIGHT CONTROL COMPUTER A PER AMM 22-11-33 O. ACCOMPLISHED SATISFACTORY OPERATIONAL CHECKS.