In our environment, you can only boot off of the hard drive or the NIC.
This keeps users from booting to a OS on a thumb drive or using a password cracker CD against our administrative accounts.
Does the BIOS update documentation state that it addresses this specific problem?
I merely downloaded the BIOS update package from the com website, double clicked and launched the installer. I even ran the BIOS installation file as an Administrator.
As a warning, y0ur users will forget how to turn on their computers… You will want to download the Dell Client Configuration Toolkit (CCTK) for Windows.