What was found
ETOPS FLT 477, OAK-HNL: CLIMBING OUT OF OAKLAND, THE MASTER CAUTION LIGHT ILLUMINATED, DOORS AND FORWARD CARGO WITH A LOSS OF PRESSURIZATION. RETURNED TO OAKLAND; UNEVENTFUL LANDING. ALL DOORS WERE VERIFIED CLOSED AND LOCKED; BIT CPC. NO DEFECTS NOTED. PERFORMED A CABIN PRESSURIZATION CHECK IN ACCORDANCE WITH MM 05-51-91-2. NO LEAKS NOTED. DECAY CHECK GOOD. FORWARD CARGO DOOR INDICATION INOP. DEFER PER MEL 52-3, CONTROL NUMBER 2611C06. DOOR IS VERIFIED CLOSED AND LOCKED BEFORE FLIGHT. AIRCRAFT RETURNED TO SERVICE.