Update Grub2 Configuration

Oct 13, 2025 by talynt.org 108 views

Introduction

When setting up a secure system, one of the most critical aspects is the protection of sensitive data, such as encryption passphrases. In this context, using a LUKS (Linux Unified Key Setup) encrypted system is a popular choice. However, when it comes to entering the LUKS passphrase, the default keyboard layout may not be suitable for all users. This is where Grub2 comes into play, allowing us to customize the keyboard layout for entering the LUKS passphrase. In this article, we will explore how to change the keyboard disposition for LUKS passphrase using Grub2 on Slackware 15.1.

Disk Partitions

Before we dive into the process of changing the keyboard disposition, let's take a look at the disk partitions on our system. We can use the lsblk command to get an overview of the disk partitions.

# lsblk
NAME               MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                  8:0    0  1.8T  0 disk
|-sda1               8:1    0   16M  0 part
|-sda2               8:2    0   512M  0 part /boot
|-sda3               8:3    0  1.8T  0 part
  |-cryptlvm        254:0    0  1.8T  0 crypt /mnt
    |-lvm-root     254:1    0  1.8T  0 lvm  /
    |-lvm-swap     254:2    0   16G  0 lvm  [SWAP]

In this example, we have a single disk sda with three partitions: sda1, sda2, and sda3. The cryptlvm partition is a LUKS encrypted partition, which contains the lvm-root and lvm-swap logical volumes.

Grub2 Configuration

To change the keyboard disposition for LUKS passphrase using Grub2, we need to modify the Grub2 configuration file. We can do this by creating a new file in the /boot/grub directory.

# mkdir -p /boot/grub/custom
# echo "set keyboard-remapping=us" > /boot/grub/custom/remap.cfg

In this example, we create a new directory /boot/grub/custom and a new file remap.cfg inside it. We then add the following line to the remap.cfg file:

set keyboard-remapping=us

This line sets the keyboard remapping to the US layout.

Grub-mkimage

To apply the keyboard remapping, we need to use the grub-mkimage command. This command generates a new Grub2 image that includes the custom keyboard remapping.

# grub-mkimage -o /boot/grub/custom/remap.img -c /boot/grub/custom/remap.cfg

In this example, we generate a new Grub2 image remap.img that includes the custom keyboard remapping from the remap.cfg file.

Update Grub2 Configuration

To apply the changes, we need to update the Grub2 configuration file. We can do this by running the following command:

# update-grub

This command updates the Grub2 configuration file to include the custom keyboard remapping.

Verify Changes

To verify that the changes have taken effect, we can reboot the system and enter the LUKS passphrase. If the keyboard disposition has been changed successfully, we should see the US keyboard layout when entering the passphrase.

Conclusion

In this article, we have explored how to change the keyboard disposition for LUKS passphrase using Grub2 on Slackware 15.1. We created a custom Grub2 image that includes the keyboard remapping and updated the Grub2 configuration file to apply the changes. By following these steps, we can customize the keyboard layout for entering the LUKS passphrase and ensure a more secure system.

Troubleshooting

If you encounter any issues during the process, here are some troubleshooting tips:

Make sure that the remap.cfg file is in the correct location and has the correct contents.
Check that the grub-mkimage command is generating the correct image.
Verify that the Grub2 configuration file has been updated correctly.
If you are still experiencing issues, try rebooting the system and entering the LUKS passphrase again.

Additional Resources

For more information on Grub2 and LUKS, you can refer to the following resources:

Grub2 documentation
LUKS documentation
Slackware documentation
Grub2, Change Keyboard Disposition for LUKS Passphrase using Grub-mkimage: Q&A ====================================================================

Introduction

In our previous article, we explored how to change the keyboard disposition for LUKS passphrase using Grub2 on Slackware 15.1. However, we understand that some users may have questions or concerns about the process. In this article, we will address some of the most frequently asked questions about changing the keyboard disposition for LUKS passphrase using Grub2.

Q: What is the purpose of changing the keyboard disposition for LUKS passphrase?

A: Changing the keyboard disposition for LUKS passphrase allows you to customize the keyboard layout for entering the LUKS passphrase. This can be useful for users who prefer a specific keyboard layout or for users who need to enter the passphrase in a specific language.

Q: How do I know which keyboard layout to use?

A: The keyboard layout you choose will depend on your personal preference and the language you are using. You can choose from a variety of keyboard layouts, including US, UK, French, German, and many others.

Q: Can I use a custom keyboard layout?

A: Yes, you can use a custom keyboard layout. To do this, you will need to create a custom Grub2 image that includes the custom keyboard layout. You can use the grub-mkimage command to generate the custom image.

Q: How do I update the Grub2 configuration file?

A: To update the Grub2 configuration file, you will need to run the update-grub command. This command will update the Grub2 configuration file to include the custom keyboard layout.

Q: What if I encounter issues during the process?

A: If you encounter issues during the process, you can try the following troubleshooting tips:

Make sure that the remap.cfg file is in the correct location and has the correct contents.
Check that the grub-mkimage command is generating the correct image.
Verify that the Grub2 configuration file has been updated correctly.
If you are still experiencing issues, try rebooting the system and entering the LUKS passphrase again.

Q: Can I use this method on other Linux distributions?

A: Yes, you can use this method on other Linux distributions that use Grub2. However, you may need to modify the process slightly to accommodate the specific requirements of your distribution.

Q: Is this method secure?

A: Yes, this method is secure. The custom keyboard layout is stored in a separate file, which is not accessible to unauthorized users. Additionally, the Grub2 configuration file is updated to include the custom keyboard layout, which ensures that the custom layout is used when entering the LUKS passphrase.

Q: Can I use this method to change the keyboard disposition for other types of passphrases?

A: Yes, you can use this method to change the keyboard disposition for other types of passphrases. However, you will need to modify the process slightly to accommodate the specific requirements of the passphrase type.

Conclusion

In this article, we have addressed some of the most frequently asked questions about changing the keyboard disposition for LUKS passphrase using Grub2. We hope that this information has been helpful in answering your questions and providing a better understanding of the process. If you have any further questions or concerns, please do not hesitate to contact us.

Additional Resources

For more information on Grub2 and LUKS, you can refer to the following resources: