As
Mutt states, Flaps 20 is not a NORMAL Flap setting for the B777 (All variants).
Flaps 20 is one of the available Flap settings for One Engine Inoperative, and for my operator, the preferred setting for OEI operations.
Done hundreds in the simulator, and 1 for real. No big deal, very straight-forward
Regards,
Old Smokey