usb_cmd=""

if [ -n "{{qn_usb}}" ]; then
   if ! [ -f {{qn_usb}} ]; then
       dd if=/dev/zero of={{qn_usb}} bs=8M count=1 >/dev/null 2>&1
       mkfs.vfat {{qn_usb}}  >/dev/null 2>&1
   fi
   usb_cmd=" -drive if=none,id=usbstick,format=raw,file={{qn_usb}} -usb -device usb-ehci,id=ehci -device usb-storage,bus=ehci.0,drive=usbstick "
fi