Well, I charged the Aura for about 3 hours or so before attempting the update (just bought it yesterday).
Anyway I've plugged it in and will let it charge sometime longer - if it does charge because there's no LED indicating anything.
What you suggested (holding etc.) is what Kobo suggested as well but it didn't work. Maybe after charging some more...
Hopefully I don't sound ungrateful or something - I really appreciate that all of you are trying to help me. I'm just really frustrated.