[ubuntu] Corrupted USB ISO

Trying to write a Ubuntu ISO (have tried both 16.04 Desktop i386 + Server i386) to a USB drive, and whatever/however I do it, I end up with a corrupted USB drive - in GParted, shows as "File System": unknown, with flags boot and hidden, and anything else seems to want me to format the drive.
Have tried writing using dd and StartUP Disk creator, with the same outcome. Thought it may have been because the drive was mounted (as Ubuntu automatically mounts the USBs), so have ensured it is not, by manually umounting at the command line - no change.
BUT, if I reboot my computer into Opensuse, can dd fine to a usable (same hardware) USB boot drive.
Anyone have any ideas?
Thanks.