Hi,
if airmon-ng can set a card into monitor mode, fernwifi is also able to do it. But, if airmon-ng doesn't rename wlanx into wlanxmon, fernwifi writes "problem occured while setting up the monitor mode ....". Here an example for such a case:

PHY Interface Driver Chipset

phy0 wlan0 b43 Broadcom on bcma bus, information limited
(monitor mode enabled)

The result of iwconfig is:

wlan0 IEEE 802.11 Mode:Monitor Frequency:2.457 GHz Tx-Power=20 dBm
Retry short limit:7 RTS thr:off Fragment thr:off
Power Management:on

airmon-ng works with wlan0 without problems.

Another problem is the setting back into the managed mode. After "airmon-ng stop" wlan0 stays in mode "monitor". I must set it with iwconfig into the managed mode.

The card has the following identification:

Network controller: Broadcom Inc. and subsidiaries BCM43228 802.11a/b/g/n

If I use my usb-wlancard "Qualcomm Atheros AR9271" airmon-ng rename the identifier into wlanxmon, and fernwifi correctly works ! Instead driver b34 the driver name for this card is ath9k_htc is used.

Bye
Rose