Could someone who is familliar with the ePub reader test these patches (one at a time) and let me know how they affect the header/footer size in ePub books when the "Show title" / "Show footer" options are unticked?
Decrease ReaderService viewport height: (libnickel.so.1.0.0.yaml)
Increase ReaderService viewport height: (libnickel.so.1.0.0.yaml)
I tried them with firmware 4.8.11073 and decreasing the height seemed to work as I would expect, the area available for book content decreased and remained vertically centred, but increasing it didn't work at all. Maybe it will give a clue where to look for a solution though.