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!
Are you guys running the avalon over wifi or ethernet? I had similar problems with a bad wifi connection: stopped hashing, no access over wifi. I came across the solution when I tried -and could - connect over ethernet and noticed a pretty bad signal/noise ratio. An interruption of the wifi connection can confuse cgminer completely.
Installing a repeater solved this issue for me and I have a Opetwrt/cgminer uptime of more than 7 days now.