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How To Set GRUB2 Resolution to Maximum Detected at Boot

Ubuntu 14

In this article, we will guide you through the process of setting the GRUB2 resolution to the maximum detected at boot. GRUB2, or the Grand Unified Bootloader version 2, is the default bootloader for most Linux distributions. It’s the first software that runs when you start your system, allowing you to choose which operating system to boot. By default, GRUB2 might not use the maximum possible resolution of your monitor, but this can be changed by editing its configuration file.

Quick Answer

To set the GRUB2 resolution to the maximum detected at boot, you need to edit the /etc/default/grub configuration file. Look for the line that starts with GRUB_GFXMODE and uncomment it, then set the value to auto. Save the file, update GRUB2 with sudo update-grub, and reboot your system.

Understanding GRUB2 Resolution

The resolution of GRUB2 is determined by the GRUB_GFXMODE parameter in its configuration file. By default, this might be set to a low resolution like 640x480. However, it can be set to auto, which tells GRUB2 to use the maximum resolution detected by your system at boot.

Editing the GRUB2 Configuration File

To change the GRUB2 resolution, you need to edit the /etc/default/grub file. This file is owned by the root user, so you need to use sudo to edit it with administrative privileges. Here’s how:

  1. Open the terminal. You can do this by pressing Ctrl+Alt+T.
  2. Type the following command and press Enter:
sudo nano /etc/default/grub

This command opens the GRUB2 configuration file in the nano text editor. sudo runs the command as the root user, nano is the text editor, and /etc/default/grub is the path to the configuration file.

Changing the GRUB2 Resolution

In the configuration file, look for the line that starts with GRUB_GFXMODE. It might look something like this:

#GRUB_GFXMODE=640x480

This line is commented out, as indicated by the # at the beginning. To change the resolution, you need to uncomment the line and set the value to auto. Here’s how:

  1. Remove the # at the beginning of the line.
  2. Change the value to auto. The line should now look like this:
GRUB_GFXMODE=auto

This tells GRUB2 to use the maximum resolution detected at boot.

  1. Save the file by pressing Ctrl+O, then exit nano by pressing Ctrl+X.

Applying the Changes

After editing the configuration file, you need to update GRUB2 for the changes to take effect. You can do this by running the following command in the terminal:

sudo update-grub

This command generates a new GRUB2 configuration file based on the default file you edited.

Finally, reboot your system to see if the maximum detected resolution is used. You can do this by clicking on the system menu and selecting Reboot, or by running the following command in the terminal:

sudo reboot

Specifying Multiple Resolutions

If the auto setting doesn’t provide the desired resolution, you can specify multiple resolutions to be tried in order. To do this, set the GRUB_GFXMODE parameter to a list of resolutions separated by commas. For example:

GRUB_GFXMODE=1600x1200,1280x1024,1024x768,800x600,640x480

This tells GRUB2 to try the resolutions in the specified order until it finds one that works.

Conclusion

Setting the GRUB2 resolution to the maximum detected at boot can make the boot menu look better on high-resolution monitors. However, keep in mind that GRUB2 uses VESA BIOS Extensions (VBE) to display the boot menu, and the maximum resolution supported by VBE may not always match the maximum resolution supported by your video card and monitor. If none of the above solutions provide the desired result, it might not be possible to achieve the maximum resolution through GRUB2.

For more information about GRUB2, you can refer to the official GRUB2 documentation.

How do I know what resolution my monitor supports?

You can usually find the supported resolutions for your monitor in its user manual or by checking the manufacturer’s website. You can also try searching for your monitor model online to find the specifications.

Can I set a custom resolution in GRUB2?

Yes, you can set a custom resolution in GRUB2 by specifying the desired resolution in the GRUB_GFXMODE parameter in the /etc/default/grub file. However, keep in mind that the resolution must be supported by both your video card and monitor.

How can I revert the changes and go back to the default GRUB2 resolution?

To revert the changes and go back to the default GRUB2 resolution, simply edit the /etc/default/grub file again and comment out the GRUB_GFXMODE line by adding a # at the beginning. Then, save the file and run sudo update-grub to update the GRUB2 configuration. Finally, reboot your system for the changes to take effect.

What should I do if the maximum detected resolution is not working properly?

If the maximum detected resolution is not working properly, it might be due to compatibility issues between GRUB2, your video card, and monitor. In such cases, you can try specifying a specific resolution in the GRUB_GFXMODE parameter instead of using auto. Additionally, you can experiment with different resolutions or consult the official GRUB2 documentation for further troubleshooting steps.

Can I set a different resolution for the GRUB2 boot menu and the operating system?

No, the resolution set in the GRUB_GFXMODE parameter applies to both the GRUB2 boot menu and the operating system. GRUB2 uses VESA BIOS Extensions (VBE) to display the boot menu, and the resolution is carried over to the operating system once it is booted.

Are there any other ways to customize the appearance of the GRUB2 boot menu?

Yes, there are other ways to customize the appearance of the GRUB2 boot menu. You can change the background image, change the font style and color, and even add a custom theme. However, these customizations require additional steps and modifications beyond the scope of this article. You can refer to the official GRUB2 documentation or search for online tutorials for more information on customizing the GRUB2 boot menu.

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