Alright, with the help of NiLuJe, bhaak, and varnie, I think I found a solution for most of the issues we're having.
I have packaged a new version of libfreetype.so. As far as I can see, this fixes the following issues:
- blank (completely empty) fonts don't occur anymore -- at least for me.
- actual font sizes of different fonts are much more homogeneous
- even the blanket screens (USB connected/update/restart messages) are now using the configured sans-serif font.
Download is here
. Install/uninstall as usual. You may get weird behavior right after installation/uninstallation (I don't know why that is). Simply restart the Kindle once or twice more in that case.
Note that it is not an absolute requirement to install this. The Kindle and the Font hack app will obviously still work if it's not installed, but with a few known flaws.