As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE AT 4000', CABIN ALT HIGH LIGHT & WARNING CAME ON INITIATED EMERGENCY DESCENT AND LT PACK OFF, LEFT BLEED EICAS MSG CAME ON DURING DESCENT THEN CLEARED. CREW DECLARED AN EMERGENCY FOR DEPRESSURIZATION AND DIVERTED TO MDT. FOUND D24 LOOSE ON HPC, TIGHTENED SOME. REPLACED LT ENGINE PRSOV PER AMM 36-11-09. A/C REMAINS NO ETOPS. SYSTEM CHECKS NORMAL. RAN ENGINE PER AMM 71-00-00, DUCT PRESSURE NORMAL. A/C RETURNED TO SERVICE.