aww darn. I was a bit late but a tool like ImageUSB can be used to zero-fill a usb drive (similar to what the HDD LLF tool can do)

zero filling a usb drive is like doing a full format; just run ImageUSB, select the usb drive that you want to completely erase, choose "Zero usb drive" and click Yes or OK "two" consecutive times, then perform the zero-fill. then remove and re-insert your now blank usb drive and you can format it again in Windows with any file system you want.