> I didn't have time to nail the cause but it could have very well been me tweaking config. I've had a couple failed Ubuntu upgrades recently, with similar be

> I didn't have time to nail the cause but it could have very well been me tweaking config. I've had a couple failed Ubuntu upgrades recently, with similar behavior ("oops, you can't boot anymore, sorry!"). And I only use it on one fairly boring machine doing fairly boring things with it—I don't tweak anything.