For the most part, a usb is a real hard drive. So, if you have a working 16 gig VM and you dd it over or use clonezilla or such to move/copy it there should be close to or a working system. It may be possible to boot to an iso of some kind in the vm and attach the usb to do this.
Clones tend to work between 100% identical equipment better. Things like drive name and mounts may have to be adjusted. Sometimes can be set generic in vm and then copy then set to correct in usb.
You may have to use syslinux on usb to get it ready.
If your vm is larger than the flash then you'd have to generally shrink it first then copy it.
Still the most accurate way would be to install this custom setup to the usb using the same steps you did to the vm. Exclude any vm specfic steps.
Last edited by jefro; 07-09-2014 at 10:27 PM.