As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE AT 360, ABOUT 4 HOURS INTO FLIGHT, LH FMC MCDU SCREEN WENT BLANK AFTER FLASHING SEVERAL TIMES. WAS OUT ABOUT ONE MINUTE. CAME BACK ON AND WORKED NORMALLY NO VTK, MAP OR SINGLE FMC MESSAGE ON DISPLAYS OR RH FMC. GROUNDED - YES. COMPLIED W/ FMC RESET PER B737-800 FIM 34-61 TASK 836 AND OPS CHECK NORMAL. ETOPS GROUND VERIFICATION TEST SUCCESSFUL.