====== Create USB Bootable Windows installation source ======
Install "wimtools" so we can use wimsplit as the .wim file is usually too big for FAT32

Extract .iso
<code>
7z x Win10_21H1_English_x64.iso -owin10
</code>

Split install.wim (in 3GB parts, as it is enough to just get two parts )
<code>
cd win10/sources
win10/sources$ wimsplit install.wim install.swm 3000
Writing "install.swm" (part 1 of 2): 0 MiB of 4654 MiB (0%) written
Writing "install2.swm" (part 2 of 2): 2737 MiB of 4654 MiB (58%) written
Finished writing split WIM part 2 of 2
</code>

Remove install.wim
<code>
rm install.wim
</code>

Create partition table and filesystem
<code>
parted -s /dev/sde -- mklabel gpt
parted -s /dev/sde -- mkpart WIN10_EN fat32 1MiB -1
parted -s /dev/sde -- toggle 1 esp
mkfs.fat -n WIN10_EN /dev/sde1
</code>

Mount USB stick and copy files
<code>
mount /dev/sde1 /mnt
cd ..
cp --preserve=mode,timestamps -Rv * /mnt/
umount /mnt
</code>

===== Install from this USB drive =====

Due to the fact that install.wim is now split we need to launch Setup.exe manually.

[[https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/split-a-windows-image--wim--file-to-span-across-multiple-dvds?view=windows-11|Split a Windows image file]]

Choose "Repair your computer" and then start the "Command Prompt".

Then find the drive that matches the USB stick (not X: as it is some runtime environment not the actual USB stick)

<code>
c:\setup.exe /installfrom:"C:\sources\install.swm"
</code>

====== Create USB bootable Windows install using Ventoy ======

Install Windows using some virtualization tool (I tested using Virtualbox as it has VHD support builtin). \\
Make sure you boot it fully after installation to make sure everything is installed. \\

Install [[https://www.ventoy.net/en/index.html|Ventoy]] to USB drive. \\
Then reformat the "Ventoy" partition in NTFS (needed for support to boot VHD files). \\
Install the [[https://github.com/ventoy/vhdiso/releases|VHDISO]] plugin to Ventoy by copying ventoy_vhdboot.img to a folder named "ventoy". \\
See instructions here [[https://www.ventoy.net/en/plugin_vhdboot.html]] \\
Copy the VHD image from the newly installed windows to the "ventoy" NTFS formatted partition. \\

Done.