Use Gigabyte Image Utility to add USB3.0 and NVME drivers to Win 7 ISO... Then use Offline Driver Pack (~20GB) to install all you need. I am about to attempt this on H370 HD3
It seems that it is good. Serg008 thank you. Is there any instructions on how to do it in the future in the new BIOS.
OK it took me a while but I finally got it working. I didn't know what I was doing wrong, but apparently I was using an old gigabyte certificate. Once I downloaded the new one from the link you provided, it worked! Thank you!