Comment 21 for bug 1603655

fglrx is the driver for my monitor, so I think that would explain the observed behavior --- if the new kernel won't load the driver, then I get a black screen but can still get a terminal.

I don't think disabling SecureBoot is an option (it's a dual-boot machine and I don't want to break something permanently), but I've found something online about using /usr/src/linux-headers-$(uname -r)/scripts/sign-file to self-sign a driver for SecureBoot. The instructions aren't working for me right now, but I'll work on that and get back to you. If that works, then yeah, we can assume that it's a SecureBoot issue.

Thank you!