Surprisingly Bitmain responded quickly but unsurprisingly asked me to return the whole unit. They did offer to give me one of their coupons to cover the shipping costs. So basically they`ve sold me something that stopped working properly after only one day, well within the warranty period and expect me to pay shipping and repay import duties if it is returned to me, and it will only be returned if they deem it DOA. But I will get a coupon (value unspecified) to help buy another unit from them. What a joke!