I thought that was from 200TH/s batch. And now we are talking about final gen1 batch - 1000TH/s. But maybe first half of this batch has been completed, hence 500TH/s is still pending.
as far as I know there was 12 Thash, then 50 Thash, then 200 Thash and then there was supposed to be 1000 Thash. So I guess the 500 is part of the planned 1000 Thash. Correct me if I'm wrong please