I know that similar questions have been asked several years ago (Access BIOS while Latitude is docked); however, I didn't understand the answer. Is it possible it display the grub boot menu on an external monitor run through a docking station?

I have an MSI GL72 6QF-405 with an NVIDIA GEFORCE GTX graphics card and am using a Dell D3100 docking station

2 Answers 2


By modifying grub, you can force the boot screen to a particular display. However, I've not found a way to have the screen displayed on both displays, which leads to the following warning:

Caveat: If the boot screen is directed to an external monitor, and it is not available, then you will not be able to see the boot screen and must boot blind [e.g. pressing return and entering password] to run Linux.

  • Open Terminal (CtrlAltT in Ubuntu).

  • Enter xrandr to determine display devices. Note which display device is currently in use, and which you wish to use during booting.

    • LVDS-1 (Low-Voltage Differential Signalling), may be used for a laptop LCD display.
    • eDP-1 is also used for a laptop LCD display.
    • HDMI-1 is the HDMI output.
    • VGA-1 is the VGA output.
  • Enter (or paste, CtrlShiftV) [use nano if you prefer it to gedit]:

    sudo gedit /etc/default/grub

  • Modify the line containing GRUB_CMDLINE_LINUX to show the preferred boot device.

    • If it is currently commented out by a leading hash sign, #, remove that symbol.

    • Add devices you wish to use, using e for enable, d for disable, and D for digital output. For example, the following should enable both HDMI and LVDS, if they are listed as HDMI-1 and LVDS-1 in the results of the xrandr query:

      GRUB_CMDLINE_LINUX="video=HDMI-1:D video=LVDS-1:e"

This may need some tweaking, e.g. disabling one device or another.

  • 1
    Thank you. I'm not willing to accept that limitation, but your answer is really thorough Sep 8, 2020 at 12:59
  • 2
    this answer is WRONG, don't even try it. GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT are used to build a command line for the linux kernel and can only take effect AFTER A KERNEL IS SELECTED FOR BOOT. it wont have any effect before a selection is made, and thus won't have any effect on where the menu is displayed.
    – Lanchon
    Mar 12 at 19:30

At the risk of sounding overly simplistic, I learned, through a bit of experimentation, that hardware engineers are aware of the issue and have responded. On my old but trusty Toshiba Satellite S55 laptop (from 2013), the monitor at boot can be selected or left up to auto-select. In auto-select mode (the default), the computer will activate an external monitor if the lid is closed on the laptop. I just tried it and it works! Definitely worth a try, but check your hardware boot settings, YMMV.

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