As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDIS 903 31-50 4215 12JAN22 MUC FACT U ON INITIAL T/O, UPON TAKEOFF THRUST ADVANCE, MASTER WARNING ILLUMINATED. NO OTHER INDICATIONS. MASTER WARNING WILL NOT RESET. REJECT INITIATED AT 30 KTS REF TSI 31-50/4218 REMOVED AND REPLACED MASTER WARNING MODULE M618 AND T/O CONFIG CARD M620