As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUAL FMC FAILURE NO FMC ON BOTH CDU'S AND NAV DISPLAY VTK AND MAP DISAGREE ON BOTH NAVIGATIONAL DISPLAYS FOR APPROX 3 MINUTES FL350 2 HRS INTO FLT RESOLVED ITSELF W/ OUT ANY INPUT W/IN 3 MINUTES. GROUNDED - YES. ACCOMPLISHED FMC RESET PER B737-800 FIM 34-61 TASK 807 BOTH FMC'S LEFT AND RIGHT BACK TO NORMAL.