As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DUAL FMC FAILURE OCCURED AT CRUISE, LASTED ABOUT ONE MINUTE BEFORE RESTORING THEMSELVES. BOTH MAP DISPLAYS WERE TEMPORARILY LOST WITH VTK FLAG SHOWING ONLY ON LEFT SIDE. GROUNDED - YES. ACCOMPLISHED FMCS BITE PROCEDURE ON BOTH LEFT AND RIGHT FMC. NO INFLIGHT FAULTS AND BOTH SENSOR PAGE SHOW NO FAULTS NO VTK ON MAP DISPLAY REF B737-900 FIM 34-61 TASK 801. NO HISTORY IN 60 DAYS.