It must be the overclocking that crashes the firmware and you MUST hard reset the whole thing. I suppose if you want to get 70ghs out of these puppies then you need to be ready to fix them everyday or create something to cut USB power and +12v with some kind of MCU... I could do it but not worth it really.
No, its not overclocking. My two has zombied from day one, before i even tried anything other than default. And one of them has only given me 40-45 for the most part since i got it.
Due to the shipping cost of them however, it's not worth it to return it from here, i'll just make sure to warn people of the low quality of these.. Too bad, other than that, i kind of like these units.