How can I make a Windows PE bootable USB from Ubuntu?

Question

I am running Ubuntu, but I need to boot from Windows PE so that I can install a firmware update (only available as a Win32 exe).

I tried following steps from this Web Upd8 guide but the resulting USB is not bootable:

1. sudo apt install wimtools (required for mkwinpeimg, below)

2. Download Microsoft WAIK ISO

3. sudo mount KB3AIK_EN.iso $HOME/waik

4. mkwinpeimg --iso --waik-dir=$HOME/waik winpe.iso --overlay=/path/to/exe/folder

5. Write winpe.iso to USB drive with balenaEtcher (also tried mkusb)

How can I copy the ISO to the USB drive and make it bootable?