My avalon unit has the exactly same issue as yours. I'd like to ask if the test firmware posted by xiangfu related to this issue?
I am using firmware 20130419. Unfortunately, I don't recall the previous firmware version I was using.
Prior to the upgrade on May 5, the Avalon unit ran without any problems.
However, after the upgrade, the miner has stopped hashing twice, and the only way to recover is with a cold reset. Is this a know issue?
Cheers!