What was found
DURING TAXI, ON ENGINE START BOTH EEC TO ALT W/ L & R ENG EEC MODE EICAS MESSAGES. CREW RETURNED TO THE GATES (BTB). MTC DEFERRED IAW MEL 73-21-1-3 NO MX ACTIONS REQUIRED. PLACARD INSTALLED. MBCB 05-04-2026. ALSO: ANOTHER ISSUE CAUSING THE (BTB), ON ENGINE START, RIGHT ENG BLEED ANNUNCIATOR AND RIGHT ENG BLEED OFF EICAS MSG. PERFORMED ENG RUN IAW AMM 71-00-00 ALL CHECKS GOOD AT THIS TIME. A/C REMAINS ETOPS 180. A/C RETURNED TO SERVICE.