Asus Z9NH-D12 - Manual (Page 111)

ASUS Z9NH-D12 Series 4-45
Boot Override
These items displays the available devices. The device items that appears on the
screen depends on the number of devices installed in the system. Click an item to
start booting from the selected device.
Launch EFI Shell from filesystem de�ice
This item is for launching the EFI Shell application from one of the available
filesystem devices.