Creating a Custom Grub2 Image

Oct 13, 2025 by wbrum.org 141 views

Introduction

When using a Linux distribution like Slackware, it's essential to have a secure and convenient way to enter the LUKS passphrase during the boot process. One way to achieve this is by modifying the keyboard disposition in Grub2. In this article, we will explore how to change the keyboard disposition for LUKS passphrase entry using grub-mkimage on Slackware 15.1.

Disk Partitions

Before we begin, let's take a look at the disk partitions using the lsblk command:

# lsblk
NAME               MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                  8:0    0  1.8T  0 disk
├─sda1               8:1    0   512M  0 part /boot
├─sda2               8:2    0  1.7T  0 part
│ ├─vg_slackware-lv_root 253:0    0  1.7T  0 lvm  /
│ └─vg_slackware-lv_swap 253:1    0   16G  0 lvm  [SWAP]
└─sda3               8:3    0   512M  0 part
  └─vg_slackware-lv_home 253:2    0   512M  0 lvm  /home

In this example, we have a single disk /dev/sda with three partitions: /boot, / (root), and /home. The /boot partition is where the Grub2 configuration files are stored.

Grub2 Configuration

To change the keyboard disposition for LUKS passphrase entry, we need to modify the Grub2 configuration file. The default Grub2 configuration file is located at /boot/grub/grub.cfg. However, this file is generated automatically by the update-grub command, so we should not modify it directly.

Instead, we will create a custom Grub2 configuration file using the grub-mkimage command. This command allows us to create a custom Grub2 image that includes our modifications.

Creating a Custom Grub2 Image

To create a custom Grub2 image, we need to create a new file called grub.cfg in the /boot/grub directory. This file will contain our custom Grub2 configuration.

# mkdir -p /boot/grub
# echo "set keyboard-layout 'us'" > /boot/grub/grub.cfg
# echo "set keyboard-variant 'intl'" >> /boot/grub/grub.cfg
# echo "set luks_passphrase_layout 'us'" >> /boot/grub/grub.cfg

In this example, we create a new file called grub.cfg in the /boot/grub directory and add three lines to it:

set keyboard-layout 'us': This line sets the keyboard layout to US.
set keyboard-variant 'intl': This line sets the keyboard variant to international.
set luks_passphrase_layout 'us': This line sets the LUKS passphrase layout to US.

Creating a Custom Grub2 Image using grub-mkimage

Now that we have created our custom Grub2 configuration file, we can create a custom Grub2 image using the grub-mkimage command.

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

This command creates a custom Grub2 image called grub.img in the /boot/grub directory. This image includes our custom Grub2 configuration.

Updating the Grub2 Configuration

Now that we have created our custom Grub2 image, we need to update the Grub2 configuration to use our custom image.

# update-grub

This command updates the Grub2 configuration to use our custom image.

Testing the Custom Grub2 Image

Now that we have updated the Grub2 configuration, we can test our custom Grub2 image.

# reboot

After rebooting, we should see the Grub2 menu with our custom keyboard layout.

Conclusion

In this article, we have learned how to change the keyboard disposition for LUKS passphrase entry using grub-mkimage on Slackware 15.1. We created a custom Grub2 configuration file and used the grub-mkimage command to create a custom Grub2 image. We then updated the Grub2 configuration to use our custom image and tested it by rebooting the system.

Troubleshooting

If you encounter any issues while following this guide, here are some troubleshooting tips:

Make sure that the grub-mkimage command is installed and up-to-date.
Make sure that the custom Grub2 configuration file is created in the correct location.
Make sure that the custom Grub2 image is created in the correct location.
Make sure that the Grub2 configuration is updated correctly.

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 learned how to change the keyboard disposition for LUKS passphrase entry using grub-mkimage on Slackware 15.1. However, we understand that some users may have questions or need further clarification on certain aspects of the process. In this article, we will address some of the most frequently asked questions (FAQs) related to this topic.

Q: What is the purpose of creating a custom Grub2 image?

A: Creating a custom Grub2 image allows you to modify the keyboard disposition for LUKS passphrase entry. This is useful when you need to enter a passphrase with a specific keyboard layout or variant.

Q: How do I create a custom Grub2 configuration file?

A: To create a custom Grub2 configuration file, you need to create a new file called grub.cfg in the /boot/grub directory. This file should contain the necessary commands to set the keyboard layout, variant, and LUKS passphrase layout.

Q: What are the different keyboard layouts and variants available?

A: There are several keyboard layouts and variants available, including:

us: US keyboard layout
intl: International keyboard layout
de: German keyboard layout
fr: French keyboard layout
es: Spanish keyboard layout

Q: How do I set the keyboard layout and variant in the custom Grub2 configuration file?

A: To set the keyboard layout and variant in the custom Grub2 configuration file, you need to add the following lines:

set keyboard-layout 'us': Sets the keyboard layout to US.
set keyboard-variant 'intl': Sets the keyboard variant to international.
set luks_passphrase_layout 'us': Sets the LUKS passphrase layout to US.

Q: What is the purpose of the `grub-mkimage` command?

A: The grub-mkimage command is used to create a custom Grub2 image that includes the custom Grub2 configuration file.

Q: How do I create a custom Grub2 image using the `grub-mkimage` command?

A: To create a custom Grub2 image using the grub-mkimage command, you need to run the following command:

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

Q: How do I update the Grub2 configuration to use the custom Grub2 image?

A: To update the Grub2 configuration to use the custom Grub2 image, you need to run the following command:

# update-grub

Q: What are some common issues that may occur when creating a custom Grub2 image?

A: Some common issues that may occur when creating a custom Grub2 image include:

The custom Grub2 configuration file is not created in the correct location.
The custom Grub2 image is not created in the correct location.
The Grub2 configuration is not updated correctly.

Q: How do I troubleshoot issues related to creating a custom Grub2 image?

A: To troubleshoot issues related to creating a custom Grub2 image, you can try the following:

Check the custom Grub2 configuration file to ensure it is created in the correct location.
Check the custom Grub2 image to ensure it is created in the correct location.
Check the Grub2 configuration to ensure it is updated correctly.

Conclusion

In this article, we have addressed some of the most frequently asked questions (FAQs) related to creating a custom Grub2 image for LUKS passphrase entry. We hope this information has been helpful in clarifying any doubts or issues you may have had. If you have any further questions or need additional assistance, please don't hesitate to contact us.