fx mkzedboot

make a zedboot USB key

usage: fx mkzedboot [-f] [--build|--no-build] <usb device>

  --build | --no-build     build (or not) the image required to run mkzedboot.
  -f                       force writing to a non-usb target.

The default for --build is defined by the "incremental" feature:
   'fx --enable=incremental mkzedboot'  defaults to '--build'
   'fx --disable=incremental mkzedboot'  defaults to '--no-build'

mkzedboot source code