Comment 35 for bug 1401532

Verification-done for bionic using grub2/2.02-2ubuntu8.12, grub2-signed/1.93.13:

I have checked loading both signed and unsigned kernels. As expected, an official, correctly signed kernel from the bionic archive is loaded correctly, and a copy of the same kernel with the key removed ('sbattach --remove <kernel>') fails to load with "invalid signature" message.