First of all, let me say that I have been in this situation… The customer "IS" or needs to be responsible for a clear line of communication… Bitmain gave me their account number to do my RMA .. I all so found out that this was not acceptable in the US in order to generate a return label. I promptly emails Bitmain back and gave them a run down on the situation and they generated the return label on their end .. I was out only a 24 hour loss in return time.. The key to this whole mess is "communication" , and don't give up on that very critical key.. What I found is that Bitmain is their to help you IF you help them help you …….. Now you can be bull headed and say that its all on Bitmain but I'm sorry, in this situation if you want to get results you will have to do some of the leg work in the communication department .. I have several S1's and an S2 … I am happy with my product other then the fact that their is a VERY small ROI that I was well aware of Bitmain is by far better then a KNC or BFL in my opinion .. The only thing that was wrong with my S2 was a bad thermal reader on one card, and I can live with that… I do wish Bitmain had a local US parts house, but all in all I'm very happy with their service ..