When installing DKMS, Ubuntu prompt you that it will be creating a new Machine-Owner key for you, and the key will be enrolled in your next reboot. Do you see that happen when you install the dkms package?
When installing DKMS, Ubuntu prompt you that it will be creating a new Machine-Owner key for you, and the key will be enrolled in your next reboot. Do you see that happen when you install the dkms package?