USB-FDD stands for "floppy disk drive" which never works with USB flash drives, so in this case you should choose USB-HDD instead. Even though a USB flash drive is not a hard disk drive choosing this option frequently works. A zip drive is a removable floppy disk storage system that is mostly obsolete like floppy disk drives, so you shouldn't ^{Then, there is the actual bootloader itself, i.e. the first bit of code that executes when a computer boots from USB. Unfortunately, HDD/USB and ISO bootloaders are very different beasts, and the BIOS or UEFI firmware also treat USB and optical media very differently during boot.} .