The link I provided above shows what we use when making our ISO’s for general use.
xorriso \
-indev Rocky-9.5-x86_64-boot.iso \ # Input ISO
-outdev test.iso \ # Output ISO
-boot_image any replay \ # Maintains all boot information
-joliet on \ # Generates joliet tree with ISO 9660 and rock ridge
-system_id LINUX \ # sets system ID has LINUX - without this, some systems will not boot
-compliance joliet_long_names \ # Allows long file names up to 103 characters
-volid Rocky-9-5-x86_64-dvd # volume ID
We don’t use -as mkisofs or any of the related switches. We simply “replay” the boot part of the ISO and make the changes we want to make. If you’re adding files, use -map. If you’re updating an already existing file, use -update.
-update /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/EFI/BOOT/grub.cfg EFI/BOOT/grub.cfg
-map /mnt/compose/9/latest-Rocky-9/work/lorax/x86_64/dvd/.treeinfo .treeinfo
If you’re only adding a kickstart, use mkksiso.
% mkksiso /path/to/kickstart.ks /path/to/dvd.iso
# or...
% mkksido --ks /path/to/kickstart.ks /path/to/dvd.iso