As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAXI OUT, CARGO SMOKE WARNING ILLUMINATED, PER QRH NR 1 CARGO EXTINGUISHER ACTIVATED. CARGO SMOKE WARNING EXTINGUISHED FOR APPROXIMATELY 30 SECONDS AFTER BOTTLE DISCHARGED. RETURNED TO THE GATE. MAINTENANCE REPLACED NR 1 FIRE BOTTLE AND BOTH SMOKE DETECTOR FOR PRECAUTIONARY REASON. OPS CHECKS GOOD.