Just a small observation, don't know if it is relevant at all in this context: My new Transcend 32GB USB3 sticks come with no less than four partitions, if I am to believe fdisk -l output (which I tend to do).
So, I start with wiping them all and creating one 32GB FAT3 partition, using plain old fdisk.
Device Boot Start End Blocks Id System
/dev/sdb1 ? 778135908 1919645538 570754815+ 72 Unknown
/dev/sdb2 ? 168689522 2104717761 968014120 65 Novell Netware 386
/dev/sdb3 ? 1869881465 3805909656 968014096 79 Unknown
/dev/sdb4 ? 2885681152 2885736650 27749+ d Unknown
Have had no problem booting any computer with plain Knoppix-to-flash installation on the repartitioned sticks so far. (Such USB3 sticks also work much faster on USB2).