There are two approaches that I usually use. The first - mkisofs, below - is what I pulled out of the Makefile that I use:
mkisofs -quiet -R -b boot/grub/eltorito.img \
-no-emul-boot -boot-load-size 4 \
-boot-info-table -o my_iso.iso iso_folder
You will need an image of El Torito. You can find more information about this approach here .
( , ) - grub-mkrescue:
grub-mkrescue -o bootable.iso iso
iso/boot/grub/grub.cfg grub. , dd USB . El Torito, (, -, DVD-), USB .