I just upgraded my Glo from 3.8.0 to 3.11.0 using the Kobo desktop app. Everything went well and all my sideloaded epubs were there including my currently read book at the correct page. I then installed the must-have kobo-nightmode_build13. It installed and restarted OK. I then held the button down and boom!, factory reset. Lost all my loaded books and now I have to load them all back up again, trying to remember what I've read and not read.
After the reset and update to 3.11.0 I re-added kobo-nightmode_build13 and it works fine although there are no books on the device now. Long day ahead re-adding all my calibre books.
Hopefully this is just a one off thing for me but thought I'd throw it out there as a data point. Scared to upgrade my wife's now...
Is there a way for Calibre to remember what books were on the device and/or what is read/unread?