I'm gonna feel like an idiot for this one!
I really liked the font from the BlackIce themes for earlier RubiXes, so I decided I'd just copy the ttf files from that theme - just clocktopia, droidserif and droidserif-bold - into the system/fonts directory and make copies of the old ones. That's it, nothing else.
I figured nothing could go wrong just by changing font files and nothing else, right? I didn't even make a backup since I had one a few days earlier. Well, when I rebooted, I would get the black bar with the clock in the new font at the top, but the boot logo wouldn't go away...and then it would loop and keep buzzing. Turns out I hadn't even bootstrapped, either, so I'm stuck in stock recovery. fffffffffuuuuuuuu.
Lesson learned, I guess. Time to hard reset/restore. And I'm guessing I can't adb in recovery or bootload.
If I did want to use those fonts, what's the safe way to do it? I'm fine with the rest of the basic theme; I just want the fonts. Thanks!