Check this site out:
https://dbeinder.github.io/kobo-nightmode/
but go forth with caution, i think i just ruined my Kobo Aura. not quite sure the firware version. but i wanted to try this hack. so i just loaded the KoboRoot.tgz into .kobo folder. ejected, and now the screen says "rebooting" it's been like that for a few hours now. I don't know what to do now....
Help?
Anyone?