>Then generate the .iso: ># cd /tmp/rhel7/ ># mkisofs -o /tmp/rhel7test.iso -b isolinux/isolinux.bin -J -R -l -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -eltorito-alt-boot -e images/efiboot.img -no-emul->boot -graft-points -V "RHEL-7.7 Server.x86_64" . >^^^ Change the "-V" label accordingly for CentOS 8 to match the CentOS 8 disk label. >And the critical command for USB drive booting: ># isohybrid --uefi /tmp/rhel7test.iso I was "thinking" all that was not needed - the second partition is "editable" - I change the file - I just need to regenerate grub right - not the whole ISO. I was hoping that is why they split this out into two partitions - for just such an occasion? Just want to add a menu option. THanks, Jerry