I installed some updates to Ubuntu Server 16.04 LTS Xenial today, and when my MacPro (Early 2008) rebooted, I was welcomed by a kernel panic and a message reading:
VFS: Unable to mount root fs on unknown-block (0,0)
I was then able to boot into GRUB2 and after selecting from the advanced options a few times, I was able to boot the machine again using the 4.4.0-53-generic version of the kernel.
Upon booting I received a crash report about the linux-firmware 1.157.6 package and that the error message was subprocess installed post-installation script returned error exit status 1
Is there some reason for this? Is there anything I should read or do to keep my machine working?
Found out that two things were wrong:
After that I cleaned up my linux-images, and ran apt-get autoremove
It now seems to be working correctly again.