It is very likely that you will not get a mobile boarding pass issued by EK ex-USA as they will want to see your passport and any visas which may be required. I haven’t received one for the last couple of years. My guess is that they are going to send you out landside to the regular check in desks but as always YMMV. Please report back and let us know for sure. Normally I have an airport change before my EK flights so I am not 100% sure but this is what I would be prepared for.