Weekly Tip 69

Dell – Disable Booting from All UEFI Devices (expect HDD)

Note: the commands listed here are for Dell models only.

UEFI makes it a little more difficult to prevent  someone from booting to PXE, USB drives, and CD/DVDs. In legacy mode, you can simply turn these off. Due to the dynamic nature of UEFI, you cannot completely disable these options from one screen in the BIOS. With these four commands (there are two for PXE), you can successfully disable everything expect for the hard drive.

To set up, you need to install Dell Command | Configure on a reference machine. Copy the X86_64 folder from the installation directory to the other machines that you manage. This can be done with any desktop management application, such as ConfigMgr. For the purposes of the exercise, I will copy the X86_64 directory to C:\cctk\X86_64. Modify the commands accordingly. If you have a password set on your BIOS, you will need to add “–valsetuppwd=<password>” to the commands.

It may not show up well on the webpage, but there are double dashes:

PXE:

C:\cctk\X86_64\cctk.exe –embnic1=onnopxe

UEFI PXE Stack:

C:\cctk\X86_64\cctk.exe –uefinwstack=disable

For CD/DVD’s, you must enable secure boot. There’s no other way to disable booting from CD/DVD. Command:

C:\cctk\X86_64\cctk.exe –secureboot=enable

USB Drives:

C:\cctk\X86_64\cctk.exe –usbemunousbboot=enable

One note on the command for USB drives – there’s no way to re-enable booting from USB from a command. This will have to be done manually from the BIOS. The same is true for Secure Boot – it CANNOT be disabled via a command.

Disclaimer

All content provided on this blog is for information purposes only. Windows Management Experts, Inc makes no representation as to accuracy or completeness of any information on this site. Windows Management Experts, Inc will not be liable for any errors or omission in this information nor for the availability of this information. It is highly recommended that you consult one of our technical consultants, should you need any further assistance.

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Matt Tinney

Professional IT executive & business leader having decades of experience with Microsoft technologies delivering modern-day cloud & security solutions.

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