Bootable Pen Drive with Grub4DOS, FreeDOS and ISO Images (e.g. UBCD)

In this post I’ll show you a really neat pen drive installation. A bootable pen drive with FreeDOS installed (no images used) and Grub4DOS to load any ISO image you want.

Start with formatting the USB-Stick using FAT32. The first thing to care about now is Grub4DOS.

You’ll need the latest version of Grub4DOS and the Installer:


Now extract them and start grubinst_gui.exe as administrator.

grub4dos part 1


Select Disk, click on Refresh and then select your pen drive.

grub4dos part 2


Click on Refresh at Part List and then select Whole disk (MBR).

If you get an error message complaining about an invalid partition table, just put –skip-mbr-test in the Extra field.

grub4dos part 3

Select Don’t search floppy and leave the rest as it is, then click on Install.

Now you should get this message:

grub4dos part 4


Next up, copy the file grldr (NOT grldr.mbr) onto the pen drive and create a new file called menu.lst.

color green/black black/green white/black white/black
timeout 30
default 0

This is the first part. It defines the color of the menu, the default menu selection and the time after which the default menu selection is executed.

Now we’ll add something to boot CD ISO images, in this case, Ultimate Boot CD. (You can add any Image you want, such as Linux live distributions or Windows DVDs , just create a menu entry for every iso)

title Ultimate Boot CD
map (hd0,0)/ubcd511.iso (hd32)
map –hook
chainloader (hd32)

You have to copy the ubcd511.iso in the root directory of your pen drive. You can also create a folder called “Images” and put it in there. Just make sure you set the appropriate path to the file.

Now let’s set up FreeDOS.

Download fdbasecd.iso from

Extract or mount it and copy the folder ODIN from FREEDOS\SETUP onto the pen drive and copy COMMAND.COM from the ODIN folder into the root of the device.

The last step is to add the following to your menu.lst to boot FreeDOS:

title Boot FreeDOS
root (hd0,0)
chainloader /ODIN/kernel.sys

If you want you can also add the following lines at the end, they should be self explanatory.

title reboot

title halt

Congratulations, your done. Now you can try it. It should look like this:

grub4dos part 5


Update 2013-06-23:
I don’t know why but it is possible that you’ll get this error message when you boot FreeDOS:

Bad or missing Command INterpreter: /P /E:256
Enter the full shell command line:

It seems like FreeDOS is searching for the file in the root directory. Anyway, all you have to do is enter the full path: /ODIN/ /P /E:256


Here are several links that helped me to work things out:


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12 thoughts on “Bootable Pen Drive with Grub4DOS, FreeDOS and ISO Images (e.g. UBCD)

  1. Pingback: Ubcd iso | Belwin

  2. Pingback: Sapphire HD 5850 OC Overclocking | Black-Pixel

  3. i tried multiple times to get this loader to work.
    booting command-list
    load segment: 0x0 system type: 0x0 sector count: 0x4
    load rba: 0x9a boot type:0=no emulation

    Isolinux 4.04 2011-04-18 etcd ………
    initial menu has no Label entries!

    any help appreciated… trying to make ubcd usb key with version 511

    • So you don’t even get to the grub4dos menu? Or do you get an error when starting UBCD? Have you done anything like in this post? Are you sure your menu.lst ist correct?

  4. You might want to mention upfront that grubinst_gui.exe is a Windows program. Stupid me, I saw all the Linux blurbs on your site and got partway through before I realized this won’t work for my linux box!

  5. I tried making a DOS usb boot drive with your method and it does not work. I get a “Missing MBR-helper” error on my netbook. On my new laptop, I cannot boot from the USB, but it’s probably due to the new UEFI boot system. So for this one I understand.

    I only want free dos on it to see if I can make an old dos game run. I tried other software that are supposed to do the job and it still does not work. For example, I tried Rufus and I get an “Invalid partition table” error message. Still, your method does not generate such message even if the extra option is not specified.

    The menu.lst is transcribe like listed here except for the boot cdrom entry. I did copy the grldr instead of grldr.mbr. I used the version 1.1 of free dos while you mentioned to use 1.0. Maybe that could be the bug, but I really doubt it.

    If you have any idea of what could be creating this problem let me know. Googling did not gave me interesting results because it mainly concerned people using the windows boot loader.

    Thank You

    • Hello,
      first of all, I’ve noticed that my recent design change messed up the display of the contents for the menu.lst file.
      Please check your menu.lst again, I’m not quite sure if the paragraphs matter.

      I’ve just tried to install it myself with FreeDos 1.1 and it worked for me.

      Have you tried to format your USB drive and start over? Maybe something went wrong without showing an error message.

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