Re: Ubuntu Upgrades/Updates
Well, for the first time in a LONG time (years of upgrading!), I encountered the "upgrade-go-boom" problem myself. Fortunately, I was able to modify the kernel parms and get 12.10 booting OK.
Version upgrades are severely complicated by the fact that STILL, Canonical has failed to provide any roll-back capability; that is, if something goes wrong after the upgrade -- you are stuck! You either have to fix it (which is not always possible since features sometimes get REMOVED with upgrades), or you have to reinstall your previous version -- from scratch.
So, I always advise folks to either (1) do a clean-install on a new partition (so the old version remains available), of (2) image off the old version using Clonezilla -- so you restore it if the upgrade goes bad.
Ubuntu 16.04 Mate, Mint 18 Mate; MS Win 8.1, MS Win10 Pro.
Will not respond to PM requests for support -- use the forums.