[Quick Tip] Tell If System Installed on UEFI Mode & Secure Boot Disabled or Not

This is a beginner’s guide shows how to tell your Linux system is installed either on UEFI or BIOS mode. And if the secure boot is disabled or not.

UEFI, the Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware. UEFI is expected to eventually replace BIOS. And Secure boot is a verification mechanism for ensuring that code launched by firmware is trusted.

In many cases you need to disable secure boot, e.g., for dual boot or loading Linux modules. And it can be done easily in UEFI/BIOS settings under boot options though some need to set Supervisor Password first in Security settings.

What if you’ve already done that and forgot it? Without reboot your machine, run following commands first to check it out:

  1. Open terminal from system application menu and run command to tell UEFI or BIOS that your system installed on:
    [ -d /sys/firmware/efi ] && echo "EFI" || echo "BIOS"
  2. And check the secure boot status, via command:
    mokutil --sb-state

That’s it. You can now take further action and enjoy!

Hi, I'm Merilyn Ne, a computer geek working on Ubuntu Linux for many years and would like to write useful tips for beginners. Forgive me for language mistakes. I'm not a native speaker of English.