[NeoDuck]

 if you're not getting the 'Press ESC for boot menu' prompt, it means SeaBIOS isn't detecting the USB stick, nothing to do with the way it is formatted. Try another USB stick or SD card, and don't bother/mess with the formatting -- writing the ISO in DD mode renders that irrelevant 

 Thanks!  I wonder if all of my USB flash drives are too big?  The smallest one I have is 32GB.  I'm going to have to find something smaller to see if it works.