Use Rufus with the following settings (disable BIOS Secure Boot first)
8.1 bing 32
mbr partition scheme for uefi
Below is the screen capture of Rufus running. I tried to use the USB bootdisk afterwards and it is working, I can run Windows 8.1 with Bing again.
However same setting but with Windows 10 64bit is not working, BIOS cannot see the USB bootdisk. So I think only 32bit works. Downloading Windows 10 32bit to try now…