Im running the standard wheezy image and my firmware is up to date
I have a BFL single connected via USB, both cgminer and bfgminer work fine but after about 20 minutes it seems to lose connection to the unit. eventually I get a 'comms error'. I've tried both usb ports, and a powered hub and still get the same result. I've also tried a few different iPad & iPhone chargers and still the same.
The only thing Im still considering might be the unit is going to sleep after a certain amount of activity and that causes the issue. Im not sure how to prevent that though yet