As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FAT- ON TAKEOFF FOR FLIGHT 4299, THE LAVATORY SMOKE DETECTOR WENT OFF. ABORTED TAKEOFF AND RETURNED TO THE GATE. MAINTENANCE FOUND NO EVIDENCE OF SMOKE OR FIRE. SMOKE DETECTOR OPERATIONAL CHECKS GOOD. PLACED APU ON MEL 49-10-1B, RSI 353032 FOR BLEED AIR CONTAMINATION. AIRCRAFT RETURNED TO SERVICE. NO PARTS REPLACED.