I guess powering the unit up and down can lead to that if you click the pool/unit settings in the same time .. as well as some bad contacts on USB cables ..
Initially all boards were "green" .. now only 2 out of four are up and connected to the pool, hashing in average with about 17MH/s. Still tinkering with the remaining boards ..
I also think that it was shaken badly during transport. One of the fan guards was touching the fan when it got here making a hell of a noise (84 dB)
0.5 BTC including shipping can be done without escrow. In the worst case you buy a doorstop, but in this case, skycoinlab did not sell me one. He did his best to help me, for which I'm grateful.
Also, thanks for the refund offer, but no thanks The fun is not being rich, but getting there .. hehe