@Barty: I was mostly referring to CFF fonts in that comment, which are usually designed for print, not screen, and thus might need a bit of upscaling if you want to use a mix of TTF & CFF fonts without having to switch font sizes every time.
@rogerinnyc: Depending on the font, this can be subtle. BCI is the closest to Amazon's default, so I'm not surprised it hasn't jumped at you

. It should be more obvious on CFF fonts, for example.
As for the reboot issue, that is very odd indeed. I can't think of how it could affect this, but we've seen very weird things happen before, so why not... ;p. What I can say is that I've never experienced it, and I've been using a custom FreeType on my multiple Kindle devices for a while now, but I'll see what I can dig up

.
If you're willing to, I'd like to take a look at some logs (
;dm in the search bar) right after a crash/reboot, see if something obvious pops up.