cd myiso/
  mkdir isomount
  sudo mount -o loop ubuntu-24.04.1-desktop-amd64.iso isomount

  rsync -a isomount/ extracted

  xorriso -as mkisofs -r -V "My AutoInstall Ubuntu Image" -o ../custom-ubuntu24.iso \
  -J -l -b boot/grub/i386-pc/eltorito.img -c boot.catalog -no-emul-boot -boot-load-size 4 -boot-info-table .

Quelle