Ubuntu 22.04 Build ISO (Both: MBR And EFI )

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Introduction

In our company, we rely on a modified Ubuntu installation ISO image to meet our specific needs. However, with the release of Ubuntu 22.04, the structure of the installation image has undergone significant changes. The removal of ISOLINUX in favor of GRUB2 has necessitated a re-evaluation of our custom ISO creation process. In this article, we will explore the steps involved in building a custom Ubuntu 22.04 ISO image, supporting both MBR and EFI boot modes.

Understanding the Changes in Ubuntu 22.04

Ubuntu 22.04 has introduced several changes that impact the creation of custom ISO images. The most notable change is the replacement of ISOLINUX with GRUB2 as the default boot loader. This shift has implications for the way we create and customize our ISO images. To build a custom Ubuntu 22.04 ISO image, we need to understand these changes and adapt our approach accordingly.

Prerequisites

Before we begin, ensure you have the following:

  • A working Ubuntu 22.04 system
  • The xorriso and grub2 packages installed
  • A basic understanding of Linux and the ISO creation process

Step 1: Prepare the ISO Image

To create a custom Ubuntu 22.04 ISO image, we will use the xorriso tool. This tool allows us to create and customize ISO images from scratch.

Install Required Packages

First, install the required packages using the following command:

sudo apt update
sudo apt install xorriso grub2

Create a New ISO Image

Next, create a new ISO image using the following command:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

However, since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-booto output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e boot/grub/grub.cfg -no-emul-boot -o output.iso input/

But since we are using GRUB2, we need to modify the command to:

xorriso -as mkisofs -r -J -L -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot<br/>
**Ubuntu 22.04 ISO Creation: Frequently Asked Questions**
=====================================================

Q: What is the difference between ISOLINUX and GRUB2?


A: ISOLINUX is a boot loader specifically designed for creating bootable ISO images. It is a lightweight and efficient boot loader that is commonly used in Linux distributions. GRUB2, on the other hand, is a more advanced boot loader that provides a wider range of features and options. In Ubuntu 22.04, GRUB2 has replaced ISOLINUX as the default boot loader.


Q: Why did Ubuntu switch from ISOLINUX to GRUB2?


A: Ubuntu switched from ISOLINUX to GRUB2 to take advantage of the more advanced features and options provided by GRUB2. GRUB2 provides a more flexible and customizable boot process, which allows for more complex boot configurations and better support for modern hardware.


Q: How do I create a custom Ubuntu 22.04 ISO image using GRUB2?


A: To create a custom Ubuntu 22.04 ISO image using GRUB2, you will need to use the xorriso tool. This tool allows you to create and customize ISO images from scratch. You will need to modify the xorriso command to include the GRUB2 configuration file and any other customizations you want to make.


Q: What are the benefits of using GRUB2 over ISOLINUX?


A: The benefits of using GRUB2 over ISOLINUX include:


    

  • More advanced features and options
    • 

  • Better support for modern hardware
    • 

  • More flexible and customizable boot process
    • 

  • Ability to create more complex boot configurations
    • 



Q: How do I customize the GRUB2 configuration file?


A: To customize the GRUB2 configuration file, you will need to modify the grub.cfg file. This file is located in the boot/grub directory of the ISO image. You can use a text editor to modify the file and add or remove entries as needed.


Q: Can I use ISOLINUX with Ubuntu 22.04?


A: Yes, you can use ISOLINUX with Ubuntu 22.04, but it will not be the default boot loader. You will need to modify the xorriso command to include the ISOLINUX configuration file and any other customizations you want to make.


Q: How do I create a bootable USB drive using the custom Ubuntu 22.04 ISO image?


A: To create a bootable USB drive using the custom Ubuntu 22.04 ISO image, you will need to use a tool such as dd or mkusb. These tools allow you to create a bootable USB drive from an ISO image.


Q: Can I use the custom Ubuntu 22.04 ISO image with other Linux distributions?


A: Yes, you can use the custom Ubuntu 22.04 ISO image with other Linux distributions, but you may need to modify the grub.cfg file to include the correct boot entries for the other distribution.


Q: How do I troubleshoot issues with the custom Ubuntu 22.04 ISO image?


A: To troubleshoot with the custom Ubuntu 22.04 ISO image, you can use the following steps:


    

  • Check the xorriso command for errors
    • 

  • Verify that the grub.cfg file is correct
    • 

  • Check the boot process for errors
    • 

  • Use a debugger to step through the boot process
    • 



By following these steps and using the information provided in this article, you should be able to create a custom Ubuntu 22.04 ISO image using GRUB2 and troubleshoot any issues that may arise.