Yesterday I logged into Windows because I wanted to stream something for friend and it's much more convenient that way. Well, as I logged in, I got a pop-up that my BIOS had an update available. I like keeping my systems up to date, so I figured “what's the worst that could happen?” Well, I learned the answer to that question.
After rebooting, my system started defaulting to booting to Windows instead of GRUB. However, every time it started loading the OS, it would BSOD with an INVALIDBOOTDRIVE error. I went on a crazy goose chase trying to figure out how to correct the issue and learned a little bit about EFI vs Legacy Boot along the way. I made a launch disk called rEFInd to help me try booting into my systems but had issues still getting into an OS. With the help of the Debian forums as well as some research of my own, I was able to clear up the issue and get back to normal.
So the main takeaway here is if you have a smoothly running system, don't just blindly make changes to the BIOS unless you're prepared to sink several hours figuring out how to fix it. And for the record, I was still able to host the stream.