Valid. In fact the (thunderbolt) power port will self-destruct over a year or two without a firmware update (overheats), Lenovo used to replace 'em for free, not sure what the situation is now. I was lucky and got mine new in box (but at the second hand price) after the bios update was available, but it's something you should look out for when buying second hand. FWIW there's also a power port in the dock connector.