Those are peculiar instructions. If you mkfs then dd I presume dd will just overwrite the fs that was just installed.
Anyway I tried writing to three different devices with or without that “trick” mentioned in the article and the pureos usb still doesn’t boot.
In general USB bootable images have to be build in a specific way. I don’t remember how exactly how.
@prolog never had to do anything special to write a bootable image myself.