Dell Diagnostic Partition
If your Dell computer has a diagnostic partition when shipped you can add it to the Grub2 boot menu and run the diagnostic utilities when necessary.
The diagnostic partition is approximately 40 megabytes placed first on the hard drive. If you use gparted to display the disk, it will appear as a physical partition called /dev/sda1. It will have the bootable flag set and be formatted with the FAT filesystem.
It isn't some kind of magic, it is just a bootable DOS system. If you are curious, you can mount it and view (or edit) the contents:
sudo mount -t vfat /dev/sda1 /mnt
Grub2 Menu Configuration
If you have already installed Ubuntu, then update-grub2 was executed to automatically probe for other bootable partitions on your system. However, the probe logic does not currently seem to be able to detect a bootable DOS system. You need to define the diagnostic partition manually.
Default Custom Menu
First you must edit the menu file which defines custom bootable partitions: /etc/grub.d/40_custom. As installed, this file will contain the following 5 lines:
exec tail -n +3 $0 # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above.
Define Dell Diagnostics Menu Entry
You should append these lines to the end of the existing file:
menuentry "Dell DOS Diagnostics (on /dev/sda1)" {
insmod chain
insmod fat
set root=(hd0,1)
chainloader +1
}Note: I inadvertantly left a space character following the closing curly bracket... this caused my custom menu item to be stored in /boot/grub/grub.cfg, but inexplicably it did NOT appear in the Grub2 menu!
Update the Grub2 Menu
Finally, get the Grub2 configuration to include your custom menu entry:
sudo update-grub2
Note: This command reports each stage of probing for bootable partitions, but it does NOT mention processing the custom menu file.
Test the Dell Diagnostics
Reboot your system and you should see that Dell DOS Diagnostics (on /dev/sda1) has appeared as the last line in your Grub2 menu. Select it to boot and run the diagnostic programs. When you exit the utilities the system will reboot to the Grub2 menu.