I just went trough 2 days and more than 30 different combination of epub testing and optimization.
I think I've found a way to optimize the slow page turn speed on sideloaded epub for firmware 2.0.0.
I opened a new thread here
https://www.mobileread.com/forums/sho....php?p=2159477 with all the details
Long story short: if you use Calibre, you can try to change a value in the epub output options.
Change the "Split file larger than" parameter from it's default value (260Kb) to the minimum value of 25Kb and then, regenerate your epub.
I've attached some screenshot showing
how to change this parameter here
How fast page turn will be with this trick?
Kepub book: 1,26 sec
Sideloaded epub: 1,93 - 3,52 sec
Optimized Sideloaded epub: 1,71 - 2,21 sec
See
this thread for the analysis, the page speed measuring method, the videos....
My optimized epub feel much better than standard epub, but they are still slower than a kepub.
This slow page turn bug need to be fixed by Kobo Dev Team.
Anyway, optimizing the epub using this "Split file larger than 25kb" trick make the firmware 2.0.0 more livable.