I tried with 6 and with custom 10 and it works. It works also never. After never I had to restart KOReader because it was blocked on never, then it worked again.
The second time I tried never it was blocked again on never, then I had a crash after going to the file manager. After that it has restarted itself (I touched the screen and pushed the buttons). And now it seems to work correctly with the desired refresh.
Where I can find the log of crash to post it if You are interested?
About color: I love my ereaders and I love KOReader (I can't install it on my Kindle

). The only problem for me could be time, but
let's try.
Edit: I maintained the file
`applications/koreader/frontend/device/pocketbook/device.lua` with the commented line as above.
second edit: now each time I escape from a book and go to the file manager I have a crash, may related or not to refresh, I am not able to guess. After 2-3 seconds KOReader restarts itself without I do nothing.