As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ETOPS SIGNIFICANT SYS - L PACK LIGHT ON EICAS MESSAGE CAME ON IN FLIGHT ACCOMPLANIED BY A LOUD HUM AND VIBRATION. PACK CAME ON AND HUM WENT AWAY AFTER ABOUT 1 MINUTE. PERFORMED FIM 21-51-00 BITE CHECK LFT PACK TEMP CONT ROLLER NO FAULTS NOTED. VISUALLY INSPECTED LFT PACK. NO FAULTS NOTED OK FOR SERVICE