I've contacted one of brcm80211 developers, and here`s the response regarding RFMON implementation :


RFMON is on the todo list but it's not currently a high priority. We're focused right now on getting the code cleaned up to meet kernel coding guidelines, and on fixing some known stability issues.

- Henry

Henry Ptasinski
henryp@broadcom.com
So, nothing left to do. seems we should just wait... !