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

Sat, Aug 27, 2011 3-minute read

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.

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

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.

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

Now you should get this message:

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 FREEDOSSETUP 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:

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: