Creating install media for High Seirra from the 21MB downloader

If you try to create install media with createinstallmedia on Sierra for High Sierra, an error will pop up that the install is not valid.

The trick is to run the 21MB downloader, let it download all the files, and NOT press reboot.

Then, go to /Applications/Install macOS High Sierra.app/Content and create a folder named SharedSupport. Then copy all the data from /macOS Install Data/. into /Applications/Install macOS High Sierra.app/Content/SharedSupport and re-run createinstallmedia WITHOUT --applicationpath. Like this: createinstallmedia --volume volumepath

--applicationpath has been deprecated for High Sierra.

It should create install media properly.

Here's a Terminal Dump
Directory structure