As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CHRONIC PROBLEMS WITH APU STARTING. REMOVED AIRCRAFT FROM ETOPS. *S/D* EXTENSIVE TROUBLESHOOTING WAS ACCOMPLISHED. MANY PARTS WERE REPLACED AND THE PROBLEM WAS INTERMITTENT APU FAILURE TO START. ON MAY 5TH, APU ENGR AND TAIL NUMBER TRACKER MET THE ACFT IN SFO AND A THIRD APU START SWITCH WAS INSTALLED AFTER PERFORMING MORE TROUBLESHOOTING. THE PROBLEM HAS BEEN FIXED WITH GOOD RESULTS AND NO MORE ALTITUDE START FULLERS.