Hey folks,
This persistent install USB kit has proven invaluable. I currently have sda1 as a 16 general purpose USB drive and the second partition as my persistent Linux install.

However, I was looking to add ms-dos to the first partition which I could load into via grub. However, at the moment all I get is a "boot error" screen.

Here's what I've added to the /etc/grub.d/ directory:
exec tail -n +3 $0

menuentry "DOS" {
insmod chain
insmod fat
set root=(hd0,1)
chainloader +1