Currently I have GRUB on my Hard Drive, which gives me the option to boot into Ubuntu, Windows, etc. When I put in my Flow OS flash drive, however, it boots into it without asking, which makes sense. What I'm wondering is how I can make it so that I have the option of booting into Flow when the flash drive is in, and that option removed when that flash drive it out.
So far I've tried putting GRUB on the MBR of the flash drive, which shows me all the options normally for GRUB instead of booting into Flow, but I haven't figured out how to add an option to boot into Flow. It seems flow uses an extlinux bootloader, so perhaps using a chainloader would work, but I've had no success with that either, it just gives me a Boot Error when I try from the command line. The stuff online about chainloaders is way over my head, so I thought I'd ask here.