Just thought I’d share in case anyone else is trying to unpack the downloaded rar files on Linux.
The unpacking seemed to go ok but failed on the install.wim file in the USB2/images directory. I tried various tools on linux and one on OSX, all of them failed the same way.
I finally pulled out an OLD Laptop with Windows Vista on it and installed WinRar and it extracted the archive on the first attempt.
Perhaps this share can save some other Linux/OSX user a few hours.
Cheers