As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL330, CABIN PRESSURE WAS LOST. FLIGHT DESCENDED TO 10,000 FT AND CONTINUED TO DTW. MASKS DID DEPLOY IN THE CABIN. CREW WAS NOT ABLE TO COMPLETELY CLOSE THE OUTFLOW VALVE. MAINTENANCE FOUND INSULATION MATERIAL BLOCKING THE VALVE AND RESECURED IT. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.