I'm having my first major problem, and since I'm still new I'm not entirely sure how to troubleshoot. Not booting at all since the latest update.

So when I got home today, my ostree0 won't boot at all. Like, gets through my bios screen and then hangs forever. Rolling back to ostree1 brings me back, so I know my PC is still in working order at least. What's the first thing I should be doing in order to figure out what's wrong?