Inside the Dell Utility Partition

An Exploration by Dan Goodell
Introduction Partition Parameters Sealed State Unsealed State Recreating Customizing
Recreating the Dell Utility Partition

(Note to reader: Booting the Dell Utility partition requires a Dell bios recent enough to include that option on its bios boot menu. If your bios does not have that capability, stop here, since there is little point in creating a Dell Utility partition on your computer. You can, of course, create a multiboot system with your own custom utility partition, but that's a different matter and doesn't use Dell's bios boot menu.)
You may wish to recreate the Utility partition if the hard disk is upgraded or replaced. For the record, installing the Dell Diagnostics utility on the hard disk is optional because you can run the same program from the Dell Resource CD (if one came with your computer -- and if you can still find it) or download it separately from the Dell website. Many people are satisfied to just run the diagnostic utility from CD when needed, and don't find it necessary to duplicate it on the hard disk. The following steps describe how to recreate the Utility partition on the hard disk if you choose to do so.

Cloning the Dell Utility Partition

A good commercial partition imaging program (BootIt-NG, Ghost, TrueImage, et al) should have no trouble duplicating the utility partition from the old disk onto the new disk, so should be considered as a first resort. However, many utilities are confused by the obfuscated partition 'type' code in the partition table.
(Note to reader: many utilities may claim to have "successfully" cloned the hidden partition, but when called upon the partition may actually fail to boot. Don't trust a utility's claim until you've confirmed the partition clone actually boots.)
For best results, the partition should be unhidden first. Use ptedit (see below) to change the partition type from DE to 06, save the change, then reboot so the change is recognized. Once the partition is unhidden, it becomes recognizable as an ordinary FAT16 partition, which most cloning tools can easily handle. Remember to rehide the partition after cloning.

Using Dell's Tools to Build a Utility Partition

The "Drivers and Utilities" CD for most recent Dell models includes a utility to create a Dell Utility partition. This utility is mkup.bat, a DOS batch file in the \upc32\uptools folder on the CD. It will only run from DOS, not Windows.

The "Drivers and Utilities" CD is bootable, but does not include the option on any of its menus. You must boot from the CD, exit to the DOS prompt, and run the mkup.bat script from the command line. Run the utility with the command: "x:\upc32\uptools\mkup  ####", where x: is the drive letter assigned to the CD drive and #### is the appropriate version number of the Dell Diagnostics utility for your system.
Warning: This utility will destroy all existing data on the hard disk, including the Windows partition! This utility should only be used on a new hard disk, or a hard disk that you are willing to wipe and start over with a completely new installation.
Note this utility requires a Diagnostics version number, and it will look for that version in the \diags folder on the CD.

Using Other Tools to Build a Utility Partition

You may need to recreate the partition from scratch if the old Utility partition was erased, the old disk is not readable or not available, or if you wish to upgrade to a newer version of the Dell Diagnostics program.

Here's how to recreate the unsealed version of the Utility partition from scratch. (Note to reader: a certain familiarity with DOS is expected here. Please don't ask me for help with basic DOS topics. The following is one way of doing things, but feel free to use your own methods to do the same things below.)
  1. Make sure you have unallocated disk space in which to create the partition. This is not a problem on a new disk, but if the disk has existing partitions, you may need use something like Partition Magic or another repartitioning tool to free up some disk space. A typical Utility partition is about 30-60 MB. (Note to reader: For compatibility it is best to position the Utility partition at the front of the disk.)

  2. Make a Primary FAT16 partition. There are many popular partitioning tools that will do this, or boot to a DOS floppy and use fdisk.

    If you are using fdisk, the choice is called a "Primary DOS" partition, and you will also need to perform a second step to separately format the partition. Reboot again and use the "format c:" command, which should default to FAT16 on a 30-60 MB partition.

    Some utilities (such as Partition Magic) simply call the FAT16 option "FAT", and the utility may format the partition at the same time it is created.

  3. Mark the partition 'active' so it will show up as drive C: in the following steps.

  4. Reboot so the changes are recognized.

  5. Make the partition bootable. Boot from a DOS floppy, then "sys c:" to transfer the system files.

  6. Copy the Dell Diagnostic program. The program (delldiag.exe) and its support files will be together in the same directory. Find these on the Resource CD or Utility CD and copy everything in that directory to C:, the root directory of the utility partition.

    Or, download the Dell Diagnostics program for your model from the Dell website, extract all files, and copy them all into C:. If you have a choice, download the CDD*.EXE or CZ*.EXE version because it's easier to extract the files from those packages than from the CD*.EXE version. If you download an 'update' version of DellDiag, you'll need to open the .EXE file with a zip program (such as PKZip or WinZip) and manually extract the files from the package.

    Note: the diagnostic program doesn't include config.sys, autoexec.bat, or dellboot.exe, so . . .

  7. Add a reboot program. Dell uses one called dellboot.exe, but any common reboot program will do. There are plenty on the web, such as,,, et al -- grab one and put it in C:.

  8. Create config.sys and autoexec.bat files. These are ordinary text files that run when the partition is booted, so use them to automatically launch delldiag.exe and then reboot at the end. Hopefully you know enough DOS to know how to do this. Here are the contents of the config.sys and autoexec.bat files Dell uses.

  9. Change the partition-type byte to DE. Boot to DOS, load a mouse driver, and run ptedit. From Step 3, the partition type should be 06. Change it to DE. (Note to reader: ptedit is tough to use without a mouse, so make sure you load a DOS mouse driver before launching ptedit.)

  10. Make Windows the active partition. The active partition is the one marked 80 in the boot column of the partition table. If Windows isn't installed yet, install it now. (It will probably make itself the active partition in the process.) If Windows is already installed, use ptedit to change the Windows partition from Boot-type 00 to 80. Remember that only one partition should be marked 80.

With Windows as the active partition, it will be the one that boots normally. The Utility partition will only boot when selected from the bios boot menu.

This recreates the unsealed version of the Utility partition, not the sealed version. (But why would anyone have a need to recreate the sealed version?)

Warning: If your computer is equipped with a Dell PC-Restore partition, that feature expects to find the config.bts file in the Utility partition. Otherwise, it cannot return the computer to a sealed state following a restore of the operating system. You will either need to recreate that file, or edit the PC-Restore partition's autoexec.bat file so it skips the step returning the system to the sealed state.
author: Dan Goodell