Multiple partitions; no Windows needed

• Get a Windows install ISO
• Create a GPT partition table on the stick
• Create a 1G Fat32 partition to store everything from the ISO *except* the Sources folder
• Create another partition, this time NTFS, to store the Sources folder.
• Copy folders, woot.
• Copy Sources/boot.wim to fat partition, create sources/ei.cfg with following text:

[CHANNEL]
Retail

Make sure to use DOS line encoding.

Make sure Fat32 partition is marked bootable etc.

Single partition; needs existing copy of Windows

do some black magic to get install.wim down to something to fit on the stick