Default Android 2.2.2 - troubleshooting a clock font switch gone wrong?

First off, using Velocity 1.2b18 on an old LG Ally. As the thread title says, it's based on (ancient by this point I guess) Android 2.2.2/Froyo.

Velocity comes with a modified lock screen font that has a square/robotic/futuristic/etc font chopped in for the numbers. Since it was about as far from matching my launcher clock font as it could possibly be, I figured I would simply switch Velocity's stock font for that of the launcher font. Others have apparently done this in the past, it seemed simple enough, so I figured...why not?

I used 7zip to grab the font from the apk it was in, dropped it into my SD card, and started the process. I did the following in Total Commander, while the phone was running; in hindsight I realize this was a terrible idea. Anyway, I copied the replacement font into the fonts folder, renamed it to Clocktopia.ttf, and renamed the old one Clocktopia.old. Then I exited and tried to lock the phone.

It tried to shut off and lock, came back up, then the screen shut off again. After that, whenever woken up, the key lights and backlight would come on, but it simply freezes on a black screen. Opening the physical keyboard (which would normally auto-unlock) does nothing, and it won't go back to sleep via the power button. Rebooting the phone, since it normally boots to the lock screen, has the same result.

"Ok," I thought, "so I'll simply remove the replacement font and re-rename the original and all will be well". And so, booting into recovery and accessing the phone from adb, I did just that. Rebooted the phone after this: same result as before. A bit of googling suggested clearing the cache when messing with fonts, so I cleared both caches and rebooted: same thing.

I've since made a nandroid of this apparently now borked android installation and restored a backup from the middle of the month (note to self: backup BEFORE screwing with things I don't fully understand next time), but my questions are...where did I go wrong? Was it that I performed the replacement while the phone was running? Why didn't restoring the original font reverse the effects, and is there any way to save the backup from its currently screwed-up state?