Enable CSM (Compatibility Support Module)

 
Select CSM (Compatibility Support Module) under the Boot Tab.
 
 
Make sure Launch CSM = Enabled
 
 
In addition, you need to have these 4 settings:
 
Boot Device Control = UEFI and Legacy OPROM
 
Boot from Network Devices = Ignore
 
Boot from Storage Devices = Legacy Only
 
Boot from PCI-E/PCI Expansion Devices = Legacy Only