As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT AT 500 FT, CREW RECEIVED AN EICAS MESSAGE FWD CARGO SMOKE. CARGO FIRE BOTTLE WAS ARMED THEN FIRED. CREW INITIATED AIR TURN BACK TO DEPARTURE, AND LANDED UNEVENTFULLY ON THE FIELD. R & R ALL FWD CARGO SMOKE DETECTORS IAW AMM 26-15-01. ALL OPS TEST NORMAL.