There is a known issue where a die with a bad core can cause that whole die, and sometimes the whole system, to stop hashing. We are working on this with the new firmware. I will post here as soon as the firmware is released. I do not know when, but I'm hoping for this week.
Would it be possible to get the firmware the IceDrill mine is using?
Yes, we're mining, though we've only recently (last 24h) been able to stabilize at a measurable, relevant rate of around 50Th/s (after the latest f/w:20140205-0 aka 0.3 and cgminer 3.12.3 updates). DT will post details on where (addresses) those proceeds are going, I shared it with him earlier.
And Phil, I know its not your business, but could you please tell someone that there are (civil) Batch 1 customers here, which are desperately waiting for their upgrade modules (and their promised MPP). With all the ASIC stuff shipping at the moment, we already have a hard time to get some fractions of our investments back, so every additional little GH/s would be extremly helpful.