The way to go is to
-
Plug the usb, and check where it is using
df -h
or in your Disk Utility app in theDevice: /dev/sdb
section. If it happens to be mounted,unmount <path/to/partition>
or press the stop button in Disk Utility. -
Create the bootable image in ubuntu, open terminal and:
sudo dd bs=4M if=$HOME/Downloads/Win10_2004_English_x64.iso of=/dev/sdb status=progress oflag=sync
-
Done!
Thanks to this source