did it on the Asiana app. When I went into seat selection it brought up a seat map of the first class cabin on the 747 combi. It had a button to switch the map to the business class cabin which is on the upper deck. I went ahead and selected first class seats and saved them, but then I got nervous and went back in and changed to business class seats. Worried that they might give away my seat if I pick a seat in the wrong class.