As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAIN'S MCDU FAILED AT 1:45 INTO THE FLIGHT, SCREEN WENT DARK, ALL LIGHTS ON MCDU ILLUMINATED. NO OTHER INDICATIONS. AFTER APPROX 20 SECONDS MESSAGE "BIT PASS" DISPLAYED THEN FULL FUNCTION RETURNED. GROUNDED - YES. REBOOTED CAPT MCDU & NORM OPS RESTORED & BITE CK OK REF B737-800 AMM 34-61-804.