As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAVATORY SMOKE ALARM WENT OFF AFTER TAKEOFF. STRANGE CAME FROM GALLEY. R & R THE LAVATORY SMOKE SENSOR IAW AMM 26-14-01 AND OPS CHECK IAW AMM 26-14-00, OPS CHECK OK FOR SERVICE. RAN BOTH ENGINES WITH AND WITHOUT BLEED 1 AND 2, PACKS 1 AND 2 AT HIGH POWER FOR 2 MINUTES NO EICAS MESSAGE OBSERVED.