As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAKEOFF ROLL, THE NR 2 ENGINE AMBER REVERSER UNLOCK LIGHT ILLUMINATED AND TAKEOFF WAS ABORTED. MAINTENANCE VERIFIED REVERSER WAS STOWED AND ALL LOCKPLATES INSTALLED. MEL 78-2A WAS ADDED. SPECIFIC PART CAUSING PROBLEM TO BE DETERMINED.