From avherald:

A British Airways Boeing 747-400, registration G-BYGD performing flight BA-217 from London Heathrow,EN (UK) to Washington Dulles,DC (USA) with 300 passengers, was enroute on a southerly Atlantic track after passing south of Ireland, when the crew reported smoke in the cabin and diverted to Terceira (Portugal), one of the Azores Islands, where the airplane landed safely.

Passenger reported, that the inflight entertainment system didn't work, later other electrical problems surfaced before the airplane diverted to Terceira's Lajes Airport.