Hi, > So I am sure that we have identified the problem.
There is still the possibility that only a boot flag is missed by the firmware. So please test also an ISO made by ... -boot_image any replay \ -boot_image any appended_part_as=gpt \ -boot_image any mbr_force_bootable=on If this does not boot, it could be because of xorriso's inconsistency between Protective MBR size and GPT size when "replay" is used. (I am hunting this in the code since yesterday.) So in case of failure, try a method which is very near to the way how original Ubuntu ISOs get built. The number 5725652 is the start block of the original EFI partition in the ISO from 10 october. If you use a different ISO as base, you need to ask xorriso or a partition editor for the start block of partition 2 and use that number. The partition size 9952 seems to be stable over all new Ubuntu ISOs i have seen in the last days: original=groovy-desktop-amd64_20201010_gpt.iso mount_dir=/mnt/iso mbr=groovy-desktop-amd64_20201010_gpt.mbr.img efi=groovy-desktop-amd64_20201010_gpt.efi.img efi_part_start=5725652 dd if="$original" of="$mbr" bs=512 count=1 dd if="$original" of="$efi" bs=512 skip="$efi_part_start" count=9952 sudo mount "$original" "$mount_dir" xorriso -as mkisofs \ -o test.iso \ -J -joliet-long -l \ -b boot/grub/i386-pc/eltorito.img \ -no-emul-boot -boot-load-size 4 -boot-info-table --grub2-boot-info \ --grub2-mbr "$mbr" \ -append_partition 2 0xef "$efi" \ -eltorito-alt-boot \ -e --interval:appended_partition_2:all:: \ -no-emul-boot \ -partition_offset 16 -r \ -appended_part_as_gpt \ --mbr-force-bootable \ -no-pad \ "$mount_dir" Have a nice day :) Thomas -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1899308 Title: failure to boot groovy daily (again) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-cdimage/+bug/1899308/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs