As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOW SPEED AIR TURNBACK DUE TO MASTER CAUTION WITH VISUAL AND AURAL WARNING AT 35KTS. AFTER FOLLOWING COMPANY PROCEDURES NO LATCHED OR INDICATED EICAS MESSAGE. DEPARTURE NORMAL. NO CMC MESSAGES. PERFORMED TAKE OFF WARNING TEST AND PASSED IAW AMM 31-52-00.