It is very possible to revive a dead battery, even with a smart charge, albeit doing it successfully is very dangerous. If you have a smart charger, you set your charger to NiCad mode, and begin charging with a current of 0.1A. This is a very long process of which you have to stand by the battery constantly, and never leave, making sure the battery doesn't start to get hot. Once you have pushed the cells back up 2.7V. After that switch over to LiPo mode, and continue charging at 0.1A until the voltage reaches around 3.1V. Increase charging rate to 1C after that. Make sure you keep the cells balanced. The battery should be able to hold near rated capacity after that, though there may be some necrotic degradation. I've done it with one of my packs and I have not noticed any degraded capacity. If you you're wondering why my pack was so bad, it was a DOA. I wasn't required to return it for an a replacement. If you're wondering why I would be stupid to try to charge a LiPo with NiCad mode, the answer to that is I read some stuff online and decided to try it out, outside of course.