As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NOTED LOUD NOISE FROM SERVICE DOOR. ACFT DEPRESSURIZED AT FL210. CREW DONNED OXYGEN MASK & DECLARED AN EMER. CREW DESCENDED TO 11000 INITIALLY & DIVERTED. INSPECTED SERVICE DOOR & SEAL, FOUND HOLE IN SEAL ON UPPER AFT CORNER. R & R SERVICE DOOR SEAL IAW AMM 52-41-07. PERFORMED LEAK CHECK OPERATIONS, CHECKED GOOD.