Chainloading an MS Windows installer DVD

[Philip Couling]

Hi

Is there any reason why I can't chainload an MS Windows Installer (on
USB)?  Currently when I try this I get "UnknownError" when I type "boot" at
the grub command line.

The MS Windows ISOs are a bit weird: found here:
https://www.microsoft.com/en-gb/software-download/windows10ISO

They are not partitioned and have a UDF filesystem instead of ISO 9660 or
FAT32. So my hardware cannot directly boot this.  But I was assuming that
all I would need to do would be ask grub to chainload the ISO as it has a
UDF driver.

I can read the Windows Boot media after I "insmod udf" and then
"chainloader /efi/boot/bootx64.efi" which results in the output
"/EndEntire".  But when I then type "boot" I get "UnknownError".

Has anyone experienced this? Any ideas about what isn't working? I freely
admit it could be a Microsoft weirdness that requires their input, I just
wanted to exhaust options here first.

Thanks