I use a Kobo "Aura" and have done so for a couple of years now. Suddenly it's started playing up. First sign was locking up so substantially that I ended up doing a full factory reset, which opened a bag of worms in that it updated it's firmware, in turn meaning I needed to update the management software (Calibre) and it's Kobo plugin. Since then it keeps locking up, and behaving oddly in other ways.
I'm thinking hardware, since these lock ups appear to happen pretty randomly, although so far not actually during reading operation (I don't think).
Anyone have any other opinion? I can't really think there's any cleaner way I can build it than that factory reset, but would it be worth trying just a factory reset and manually load some stuff (ie not using the Calibre software)?