I try to combine Grub4Dos and FreeDos, but unusual several times.
I find the site finally. It work.
http://black-pixel.net/bootable-usb-stick-with-grub4dos-freedos-and-iso-images-e-g-ubcd.html
simply description
1.Start with formatting the USBStick using FAT32 by USB Disk Storage Format Software or the others.
2.Download grub4dos.zip to Run grubinst_gui as Administrator. Refresh Part List fisrt. choose Whole disk(MBR) and install Grub4Dos to USBStick.
3.Copy the file grldr and menu.lst onto the Root of USB Falsh Drive.
4.Download fdbasecd.iso and Extract or mount it.
5.Copy the folder ODIN from FREEDOS\SETUP onto the USBStick and Copy Command.com from the ODIN folder into the Root of the device.
6.Add the following to menu.lst to boot FreeDOS
title FreeDOS
root (hd0,0)
chainloader /ODIN/kernel.sys
boot
If you want you can add the following lines at the end, they should be self explanatory.
title reboot
reboot
title halt
halt
MSDOS can also add the system files to the root of the device.(IO.sys,MSDOS.sys and COMMAND.COM)
Add the following to menu.lst
title DOS
chainloader /io.sys
