Create a bootable USB disk for Windows installation from MAC

1. Ensure your Mac has wimlib. If not, install it by

   brew install wimlib

2. Insert USB disk. Ensure the disk ID by

   diskutil list

   The ID of the USB disk is probably be something like /dev/disk2

3. Format the USB disk by

   diskutil eraseDisk MS-DOS "WIN10" GPT /dev/disk2

4. Download the windows ISO file (e.g., ~/Downloads/win10-Eng-x86.iso)

5. Mount the windows ISO

   hdiutil mount ~/Downloads/win10-Eng-x86.iso

6. Because the file install.wim is too large to copy over to a FAT-32 formatted USB drive, we need to copy it over separately.

   rsync -vha --exclude=sources/install.wim /Volumes/WIN10_EN-US_DV9/* /Volumes/WIN10

7. Split install.wim into 2 files and copy them to USB.

   wimlib-imagex split /Volumes/WIN10_EN-US_DV9/sources/install.wim /Volumes/WIN10/sources/install.swm 3800

VIOLA!