As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOUD BANG AND THE CABIN ALTITUDE STARTED TO CLIMB COULD NOT CONTROL PRESSURIZATION. EXECUTED EMERGENCY DESCENT AND PROCEDURES. CABIN OXYGEN MASKS WERE DEPLOYED. FOUND ACM DUCT DISCONNECTED. INSPECTED DUCT AND CLAMP NO FAULTS FOUND, INSTALLED, AND PRESSURIZATION CHECKED GOOD.