As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RTB DUE TO C1 DEMAND PUMP EICAS MSG. CHECKED ON GROUND-OK. AT REQUEST OF MCC PERFORMED SWAP BETWEEN CENTRAL HYD PUMP 1 AND 2 FOR TROUBLE SHOOTING AND CONVENNCE AS AMM 29-11-02-004-001 AND AMM 29-11-02-404-018. ETOPS CATEGORY 'E': PROBLEMS WITH SYSTEMS CRITICAL TO ETOPS.