followed by:
Ensure all necessary drivers are built into the linux image!
depmod: ERROR: could not open directory /lib/modules/4.4.0-59-generic: No such file or directory
depmod: FATAL: could not search modules: No such file or directory
depmod: WARNING: could not open /var/tmp/mkinitramfs_McREc1/lib/modules/4.4.0-59-generic/modules.order: No such file or directory
depmod: WARNING: could not open /var/tmp/mkinitramfs_McREc1/lib/modules/4.4.0-59-generic/modules.builtin: No such file or directory
/var/tmp/mkinitramfs_McREc1/lib/modules is certainly missing. Can I recreate it?
I was doing an apt-get upgrade, which completed with those warnings. The referenced duplicate applies to an update-initramfs which I was not doing (intentionally). Perhaps this is implied by apt-get upgrade?
Subsequent apt-get upgrade completes without those warnings. I'm just concerned that the firmware was not updated but other modules were.