The messages about \EFI\BOOT\fallback.efi are harmless noise from shim; you can disregard those.
Do you have any way to confirm that it's actually booting from the CD when in secure boot or UEFI-first mode (e.g. drive noise or activity lights)?
The messages about \EFI\BOOT\ fallback. efi are harmless noise from shim; you can disregard those.
Do you have any way to confirm that it's actually booting from the CD when in secure boot or UEFI-first mode (e.g. drive noise or activity lights)?