As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMB-OUT THREW FL240 ON EICAS MESSAGE "EMER LT NOT ARMED" AND "ELEC EMER ABNORMAL". RAN CHECK LIST PER AOM VOL 1. CREW ELECTED TO RETURN TO LAX. DECLARED AN EMERGENCY. AIRCRAFT LANDED AND RETURNED TO THE GATE WITHOUT FURTHER INCIDENT. FOLLOWED ETN EM-24-023 REMOVED AND REPLACED ELECTRICAL CONTROL PANEL IAW EMB EM 24-00-01. ALL REQUIRED CHECKS CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE.