As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CARGO FIRE DETECTION LOOP LIGHTS ILLUMINATED AFTER DEPARTING IAH. THE AIRCRAFT WAS RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE FOUND NO EVIDENCE OF FIRE. THE COCKPIT FIRE SUPRESSION PANEL WAS REMOVED AND REPLACED IAW MM 26-23-10 AND 26-16-10. OPERATIONAL TESTS WERE GOOD.