It looks like the Ubuntu default installation ISOs (18.10 and 18.04.1) from Ubuntu.com are still missing /EFI/BOOT/mmx64.efi. Getting the same error on Asus Sabertooth S170 Mark 1 motherboard on fresh install. Can’t install Ubuntu due to missing mmx64.efi error.
It looks like the Ubuntu default installation ISOs (18.10 and 18.04.1) from Ubuntu.com are still missing /EFI/BOOT/ mmx64.efi. Getting the same error on Asus Sabertooth S170 Mark 1 motherboard on fresh install. Can’t install Ubuntu due to missing mmx64.efi error.