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Booting from a USB with a locked down BIOS on Dell with an encrypted hard drive


Today I wanted to install Ubuntu from a USB drive (as the machine had no CD drive) on a Dell machine with Windows 7 and an encrypted hard drive. On most machines this is fairly simple:

  • Start the machine and go into the BIOS
  • Change the boot order so that USB is before hard drive or anything else
  • Exit the BIOS
  • The Ubuntu installation on the USB should now kick in
  • Simply follow the rest of the installation steps

I Googled to find out what I had to press to get into the BIOS on a Dell machine and found that it was F4. When you turn the machine on continuously keep pressing F4 until you are in the BIOS.

The problem was that as soon as I managed to get into the BIOS I saw that I could not change anything (including the boot order). It required an admin password and neither my Windows login password nor my hard disk decryption password were sufficient.

I explored a number of options like installing an additional partition on the machine's encrypted hard disk (from within Windows). But I abandoned this option as the potential solutions I found did not make it clear whether or not this would work with an encrypted hard disk - and the solutions could have broken something.

Luckily after a bit more searching I came across this post. There are apparently advanced boot options that allow you to bypass the BIOS and change the boot order.

I promptly tried using F8 on startup only to see a little message after the Dell logo saying that F12 goes to the temporary boot order menu, after which the machine proceeded to go to the drive encryption unlock screen - the machine was continuing with the boot process using the original boot order.

I then simply shut down, started up again and kept pushing F12 and bingo it worked! I was prompted with a screen called something like "Temporarily Change Boot Order". I moved USB to the top, exited this screen and was prompted with the Ubuntu installation process - it worked :D

In summary I found that the following is the case in terms of Dell startup keys that you can push (this table is not exhaustive):

Function KeyDescription
F4Goes into the BIOS where you may need an admin password (not likely to be the same as your machine password)
F8Does not let you choose the boot method like some other laptops, simply continues with the boot process
F12Goes to a temporary boot order menu where you can switch to whatever method you desire (even if your bios are locked with an admin password)