Additionally (due to personal experience) it might be worth checking whether linux-image-extra-4.4.0-77* got installed. Not sure how that could happen but it seems update-manager offered to install linux-image and linux-image-signed without any of the other packages which should be installed at the same time (I had no headers either which impacts anything dkms related).
This morning, from an older kernel boot, an "sudo apt-get update; sudo apt-get dist-upgrade" was installing the missing kernel packages.
Additionally (due to personal experience) it might be worth checking whether linux-image- extra-4. 4.0-77* got installed. Not sure how that could happen but it seems update-manager offered to install linux-image and linux-image-signed without any of the other packages which should be installed at the same time (I had no headers either which impacts anything dkms related).
This morning, from an older kernel boot, an "sudo apt-get update; sudo apt-get dist-upgrade" was installing the missing kernel packages.