Thanks for the tip, I did end up trying ckolivas 1.2.5 and it improved the HW error rate quite a bit on the one working ASIC lol. 
Should have flashed that version right from the get-go. Other ASIC still doesn't even seem to be recognized, though.
You too? Interesting, now I'm really wondering what that does. Might be time to crack out the threading disassembler :-) Should have flashed that version right from the get-go. Other ASIC still doesn't even seem to be recognized, though.Quote
Heatsink was snugged down tight and everything looked good when I had the case off. Only potential problem I can think of is one of the ASICs isn't entirely covered by the aluminum heatsink, actually a thread on the BFL forums about this. I didn't think too much of it when I first got it and opened it up since I didn't figure BFL would ship them out like this if it could cause problems, but almost wonder now if maybe that created hotspots on the ASIC or caused it to get hot enough to go belly up. Of course quieter/lower RPM fan and overclocking probably didn't help either, but for all I know it would have gone out sooner rather than later because of this even running it stock.
Mm. How tight was tight? I've been snugging the bolts down using a t8 torx bit by hand without handle or anything, pressing down on the sink and plate and snugging it down just enough to take out the slack. Finger tight, counting on the artic pad to do the work of transferring the heat. When I first took off the plate it was easy to remove with fingers on the torx bit, so I used that as the measurement of torque to snug it down.Maybe one of the chips broke a bga connection or something. Do you have air tools to try and refloat it?
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I may have to try taking the heatsink off sometime and inspecting everything. Or may just leave well enough alone considering it's still hashing at 4GH/s or so.
Hadn't thought about possibility of a bad BGA joint, I don't have a reflow station and proper tools, though, closest thing I'd have is an adjustable temp heat gun.But as mentioned I think part of the chip being exposed and not covered by the heatsink might have been what did the one ASIC in, though. Had figured it was by design, didn't even realize it was a defect until after I had already flashed it, then I had seen the thread on BFL forums about it. Too late to request an RMA since firmware has been flashed. Couldn't hurt to ask I guess but doubt they'd grant one.