printf $(sudo du -sx --block-size=1 ~/iso_workspace/squashfs-root | cut -f1) \ | sudo tee ~/iso_workspace/extract-cd/casper/filesystem.size Regenerate the MD5 checksums:
Ubuntu, Live CD, ISO Remastering, SquashFS, Chroot, Customization, Linux Deployment 1. Introduction The ability to create a customized, ready-to-run Ubuntu Desktop ISO is critical for organizations requiring consistency, reduced setup time, and offline installation capabilities. While tools like systemback and Cubic exist, they often lag behind Ubuntu release cycles or introduce unnecessary complexity. This paper describes a low-level, scriptable method using standard Linux utilities ( squashfs-tools , xorriso , chroot ) to produce a fully functional custom ISO. ubuntu desktop iso
~/iso_workspace/ ├── original_iso/ (mounted ISO contents) ├── extract-cd/ (copied ISO files) ├── squashfs-root/ (extracted filesystem) ├── custom_iso/ (new ISO staging) └── custom.iso (final output) 3.1 Extraction Phase Mount the official Ubuntu Desktop ISO (e.g., ubuntu-22.04.3-desktop-amd64.iso ) and copy its contents: This paper describes a low-level, scriptable method using
sudo cp /etc/resolv.conf ~/iso_workspace/squashfs-root/etc/ sudo mount --bind /dev/ ~/iso_workspace/squashfs-root/dev sudo mount --bind /proc/ ~/iso_workspace/squashfs-root/proc sudo mount --bind /sys/ ~/iso_workspace/squashfs-root/sys Enter the chroot environment: This paper describes a low-level
mkdir -p ~/iso_workspace/original_iso sudo mount -o loop ubuntu-*.iso ~/iso_workspace/original_iso rsync -av ~/iso_workspace/original_iso/ ~/iso_workspace/extract-cd/ sudo umount ~/iso_workspace/original_iso The live filesystem resides in casper/filesystem.squashfs :
