Comment 26 for bug 1848797

Tested several times from a 19.04 snapshot: as soon as proprietary drivers are used (in my case virtualbox-guest-dkms-hwe) the upgrade will fail and leave grub in this crippled state. Also I cannot deinstall those drivers through a package manager before the upgrade.

But it would be nice if someone else can confirm that this is related to proprietary drivers.