As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE, THE APU FIRE WARNING SYSTEM ACTIVATED, SYSTEM-A FIRE LOOP DETECTOR FAULTED, FIRE BOTTLE WOULD NOT DISCHARGE AND PULLED CIRCUIT BREAKER. AIRCRAFT CONTINUED TO SFO AND LANDED WITHOUT INCIDENT. REPLACED FIRE BOTTLE, OPERATIONAL CHECK GOOD.