As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT CRUISE CREW RECEIVED APU FIRE INDICATION AND DISCHARGED FIRE BOTTLE, APU WAS OFF. INSPECTED APU AND FOUND NO EVIDENCE OF FIRE. FOUND A-LOOP A8 CARD BAD PER MM 26-15-00 & 49-11-00. FURTHER TROUBLESHOOTING REQUIRED, FIRE BOTTLE ON DMI.