As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT NOT GROUDED: PILOT DECLARED EMERGENCY INBOUND TO ORD ON ACCOUNT DEGRADED BRAKES. BRAKES AMBER CAUTION MESSAGE AT FL350. MAINTENANCE FOUND NO ACTIVE FAULTS. FOUND MAINTENANCE MESSAGE 42-58521 IN FAULT HISTORY. ACCOMPLISHED B787 FIM 42-40-F2-V2A-421A-A. RDC 02 GROUND TEST PASSED. SUSPECT INTERMITTENT FAULT.