I stated in my previous post, how horrible Gigabyte motherboards are. I continue to do the same now.
Basically Microsoft Gigabyte's hybrid EFI is nothing but a piece of Windows software which enables Windows to access 3+TB hard drive.
There's nothing EFI in the BIOS. It cannot boot GPT disks, it cannot run EFI applications and it does not provide any EFI API to the OS.