I'm trying to modify them as follows :
isolinux/menu.cfg
LABEL English (en)
SAY "Booting English (en)..."
linux /live/vmlinuz boot=casper APPEND file=/cdrom/preseed/preseed.cfg auto=true initrd=/live/initrd.gz boot=live components locales=en_US.UTF-8 quiet splash intel_iommu=on
boot/grub/grub.cfg
menuentry "English (en)" {
linux /live/vmlinuz boot=casper APPEND file=/cdrom/preseed/preseed.cfg auto=true initrd=/live/initrd.gz boot=live components locales=en_US.UTF-8 quiet splash intel_iommu=on "${loopback}"
initrd /live/initrd.gz
}
I'm not even sure that it's correct,mostly because the grub.cfg file uses two command lines. The second one is "initrd /live/initrd.gz". I'm not sure if it should be there or if I should delete it.
Mario.