This works great with
ixtab's patcher (for 5.1.0 only):
https://www.mobileread.com/forums/sho....php?p=2077066
It brings back the original "no add" screensavers (which you can replace), and gets rid of the ad at the bottom of the desktop. All of the usual moral arguments apply, so they do not need to be discussed here.
A nice joke screensaver splices a desktop snapshot with a standard screensaver image, with a partial diagonal splice and a corner with gray streaks, so it looks like a classic broken eink display when it is in screensaver mode.