Update:
I updated my Nook to 53.0.66 (that's the latest for mine). And it's just awful. The font sizes are even more unusable than they were. And the text is definitely more faded.
I don't think there is a way to downgrade an eink Nook?
Anyway, I had to redo my embedded sizes. The new base font size is now 10.6 and I use the 4th size from the left.
What is with all the rubbish updates recently?

Both Kindle and Nook. And you can't go back to the previous firmware on either.