Patrick O'Callaghan wrote:
Pendrives often have more than one partition. Format the largest one and use that. The others are for useless builtin software which only runs on Windows. You may or may not be able to remove them with fdisk (some drives are highly non-standard in this respect).
Search for U3 and how to remove it.
Windows only and it can cause issues with other USB hardware. I have seen it in action and the need to unplug USB hardware to get it to work.