The ability to use the USB memory stick as a boot device is 100% bios-dependent. If your BIOS supports it, it'll work. If not, it won't. Simple as that.
IF your BIOS supports it, just do what you'd do to make a FLOPPY bootable - put MSDOS.SYS and IO.SYS on it as well as a COMMAND.COM, and you're done.