As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL380 RECEIVED CABIN ALT WARNING. CABIN ALTITUDE WAS AT APPROX. 12,000FT. NO FAULT LIGHTS OR OTHER INDICATIONS. DIFFERENTIAL PRESSURE WAS 6+. DONNED O2 MASKS AND PERFORMED EMERGENCY DESCENT TO 15,000FT AND THEN REGAINED CONTROL OF CABIN PRESSURE AT 15,000FT AND 4.6 DIFF PRESS. EMERGENCY WAS DECLARED. MAINTENANCE REPLACED CABIN PRESSURE CONTROL PANEL AND OUTFLOW VALVE ASSEMBLY. MAINTENANCE ALSO REPLACED THE AFT CARGO DOOR SEAL DUE TO TEARS AND A PIECE MISSING.