Does the problem occur during throttling?
Do you always specify "bitforce:" on the front of the serial device specification?
One change that I added (that's in 2.6.0 and 2.6.1) is there is now a timeout in BFL if you specify "bitforce:"
(there was always a timeout for BFL if you didn't specify "bitforce:" so I changed it work the same way in both situations)
Thus in the log there should be a message saying there was a timeout at the time the problem occurred if that is the cause of it.
(BFL needs to be able to timeout rather than hang if something goes wrong on linux - it used to hang sometimes when there were comm errors)
However, I guess it could be LP related when it tries to abort work that could be during a throttle?
If you can get it to fail either see if there is a timeout message (and post a pastebin of the log for up to 1 minute before it happens) or if there is no timeout message, run it in "-D" debug mode and post a pastebin of the last minute or so of that log up to when it fails
Or course, visiting FreeNode IRC #cgminer will be easier ...
My testing of this is on my BFL that has hardware issues lately so I put the fastest bitstream on it and thus was expecting to see any possible problems
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
But if it is during an LP then that's not easy to make happen ...
Edit: oh there was also another change that luke-jr did at the same time (I didn't notice) - so I guess it could be either of our changes.
https://github.com/ckolivas/cgminer/commit/cf36331d815e7b87131d547b92b9ceaa218d114dMy devices aren't throttling, and yes I always specify "bitforce:". I also don't believe the problem would be related to a long poll, since both machines would have received long polls near the same time, but one started having singles stop hashing much sooner than the other. I think that makes sense anyway, I'm no expert.