Thanks for the pointers. I just read the instructions and downloaded the patches and firmware and looked it all over and I've decided it's just not worth the effort for enabling bolder fonts. I understood it well enough. I think I did it once before to get a different feature on my older Kobo Glo. I'm not sure it was this exact same patch set but it was pretty much the same thing.
Anyway I don't doubt that I can do it but I have 3 Auras and it's just not worth the trouble. When you get to my age you might understand.
I do like slightly bolder fonts but it's a very minor issue for me. I can read fine either way.
Thanks for showing me the links.
Barry