This one isn't working for me. I used notepad++
to edit the file. After adding the fonts in the new font folder, ejecting and restarting I had the same font (which I could not change via Aa) and none of my content would open.
Even after reverting back to the original version of reader.pref file, I still could not open any content. I've just done a factory reset and all is well again.
Here are some images, maybe someone could tell me where I made my misstep.