As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: EMERGENCY POWER ASSIST SYSTEM MESSAGE ON 2R DOOR. MAINTENANCE REPLACED THE EMERGENCY POWER ASSIST SYSTEM MODULE PER AMM DMC B787-A-52-11-21-OOA-720A-A AND ACCOMPLISHED INSTALLATION TEST SOFTWARE LOAD AND SQUIB OPERATIONAL CHECK.