Originally Posted by Airframe

I don't think you need to worry to much, downgrading overall is quite rare even more so is downgrading from First Class. I have not met anyone who has been.
I think the main reason it occurs is the switching of planes from a 3-class config to a 2-class config. There is not really anyway one can avoid the above scenario if it happens but you should be compensated in any case.

According to schedules your planes should be as below : -

EK12 LGW-DXB = Boeing 77W
EK09 DXB-LGW = Airbus 332

Don't worry and enjoy the Emirates First experience.