As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED ENROUTE TO MIA DUE TO FMS 1 FAILED. FMS 2 WAS ON MEL. FLIGHT LANDED SAFELY IN MIA WITHOUT FURTHER INCIDENT. MAINTENANCE FOUND FAULTS OCCUR AFTER POWER TRANSFER. FAULT EXTERNAL DIST/BUS FAULT ON BUS POWER CONTROL UNIT AND BUS TIE BREAKER FAULT ON GENERATOR CONTROL UNIT. RESET BOTH UNITS. COULD NOT DUPLICATE FAULTS AFTER RESET. BUS POWER CONTROL UNIT REPLACED PER AMM 24-41-21 AS A PRECAUTION.