Why does EFI Partition unmount after ejecting?

Computer from which I am creating the bootable USB is a 2017 MacBook Air, running the latest Mojave 10.14.5.

Spec list for the target computer, already running Windows 10:

AMD Ryzen 5 1400@ 3.7Ghz

MSI Rx 580

MSI B350 Bazooka.

So, I was trying to make a Ryzen bootable USB stick, following Hackintosher's Guide for a Fresh Ryzen Install, and I ran into two issues: first of all, whenever I applied the Install to High Sierra (I got the High Sierra from the App Store) to the USB, the folder .IABootFiles and the .IABootFilesSystemVersion.plist, as well as the .IAPhysicalMedia files aren't created; secondly, when ignoring this issue, and when trying to mount the EFI partition to the USB using Clover Configurator, it would mount all right, but whenever ejected and reinserted it would appear as if the EFI partition was never even mounted, and when reopening the "Mount EFI" section, and scrolling down to my "Install MacOS High Sierra" USB, it would not say open Partition, but it would be greyed out and instead say Mount Partition. When trying to boot it, again, the EFI partition would not even show up as a boot option. HEEEELLLP!