As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING C-CHECK MAINTENANCE FOUND APU FIREWALL CRACKED ON THE INSIDE, BETWEEN STRINGERS 9R AND 10R AT THE 3 O'CLOCK POSITION. MAINTENANCE INSTALLED REPAIR DOUBLER ON APU FIREWALL IAW SRM 53-32-13 FIG 204. AIRCRAFT WAS APPROVED TO RETURN FOR SERVICE.