As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT ENGINE DRIVEN GEN DOES NOT POWER ELECTRICAL SYSTEM AFTER LEFT ENG START APU WAS SHUTDOWN AND ALL ELECTRICAL POWER WAS LOST LT/RT GEN SHOWS GCU ON BPCU. CLEAR BPCU AND RESEAT LT GCU RAN LT AND RT ENG GEN OPS AND INDICATION NORMAL OIL LEVEL NORMAL ON LT IDG ETOPS CATEGORY 'E': PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS