For example, while running Windows installation media, it's possible to summon CMD and use tools like diskpart, bdcedit, etc from X:\Sources
.
The reason is a tool called gptgen, which converts an MBR partition table to GPT without data loss. And I need to run it live on installation.
And so I need to use that third party tool on installation, but I can't. I tried to copy the executable to /sources directory of an installation media, but it seems that windows builds a dynamic filesystem, and you can only use the content which is on default .dll's.
So how to add that program to the installation to be able to use it?