I don't know how to get a message to ckolivas, but I'm testing the current master branch of cgminer and one feature that was added is fan speed control (OP code 143). However, I keep getting the error that OP_CODE 143 is unhandled.
Is it possible that I have an older revision of the board/firmware something that doesn't support controlling the fan speed using that op code?
That's in the new firmware that's coming soon. Sorry, until we complete testing we cannot release it. I'll say it again; Until the new firmware comes out, you're best bet is to run 3.9.0hf2 that I've posted here.
-Phil