Could you please tell us what you've tried so far? Do you get an error or does it simply doesn't work?
I'm sorry I haven't been able to tried it myself, but I think maybe if you don't get an error message, it could be set but not configured, so check this link there's monitor mode configurations, why don't you try it and if you succeed I invite you to post your results in the community.
Thanks for following up. It simply doesnt work. These are the steps I have followed, I may be doing something wrong.
ifconfig wlan0 down : The problem start here. When I run this command and then run ifconfig again, i see that wlan0 no longer has an IP associated with it this is what I expect. However, if I run ifconfig again just a few second later the IP address is back. This makes me think the board is not actually setting the hardware correctly but is getting inaccurate feedback from it.
iwconfig wlan0 mode monitor: Same thing. I set the board to monitor mode, it says its in monitor mode for a second and then goes back to managed mode.
Am i missing a step? this is how i do it on almost all posix systems.
Another interesting observation. So to get around this problem I temporarily cleared my wpa_supplicant so that wlan0 wouldn't connect to a network by default. On doing so the board did "seem" to stay in monitor mode however i was unable to change the frequency channel:
root@edison:/home# iwconfig wlan0 channel 6
Error for wireless request "Set Frequency" (8B04) :
SET failed on device wlan0 ; Operation not supported.
Not sure what the problem is here.
Oh and one more thing, I tried running tcpdump after setting the board up in monitor (after reomving the wpa_supplicant). I set the filter to pick up 802.11 frames and received no data.
We reviewed the BCM34341 driver of the Edison's wireless adapter and it seems Monitor Mode is not supported.