Well, no matter what happened with my console and firmware, the console won't power on at all anymore. No LED or anything. With the new board in the mail, I figured I'd play around with it some more, and after one more attempt at a firmware update and using a different program to format the card, it just straight up refuses to turn on. Interesting. If it wasn't a hardware failure before, it definitely is now!
All that aside, now I get to look forward to the excitement of receiving a new board, which for some reason is almost as exciting as when the system was in the mail in the first place, haha