I almost got a new Cybook Odyssey frontlight HD yesterday because my gen3 had died out.
The reason was a busted on/off switch probably from usage after all these years. I tried to change it with one of the the four switches that are on the side of the gen3 (which I don't think I have ever pressed :P ) but it worked only for a couple of days and the switch broke of the motherboard (I am not an expert solderer). Also I managed when removing it to remove two tiny resistors that are below the switch. So I called the day of then and decided to buy a new one.
BUT yesterday a friend of mine who is very good at soldering managed to change that. Now everything is back to normal so I will delay the purchase of a new e-reader until the die hard gen3 actually dies...