Meanwhile, of course, frustrating no wireless connection.
keys combination, BUT wlan0 (and me) struggled to acquire an IP address from a router restored to factory defaults (no filter, no security, no firewall) for a whole month. Now wlan0 is created in NM, status: associated, wireless LED is up and responding to Fn +F. After that, I was able to kldload iwn6000g2bfw, kldunload it, no need to kldload if_iwn already loaded at boot, no succes to kldunload if_iwn (no reboot but " can't find if_iwn.ko file" message). and 3 (xmj's post) with a small but necessary additional step to b64encode the. After that, the iwn0 interface appeared in Network Manager but "no carrier" and no wireless flashing LED.