Hello,
I have a problem with my edimax Realtek RTL8188CUS wifi adapter. On my laptop with kali-linux 2.0 and kali-linux 1.1.0 installed I can simply switch into monitor mode with airmon-ng. On my raspberry pi 2 with kali-linux 2.0 installed I am not able to activate the monitor mode. The normal managed mode works on all systems and I am able to connect to wifi access points.

Code:
lsusb pi:
Bus 001 Device 005: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]
Code:
dmesg pi:
[  677.058439] usb 1-1.3: new high-speed USB device number 5 using dwc_otg
[  677.160101] usb 1-1.3: New USB device found, idVendor=7392, idProduct=7811
[  677.160131] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  677.160150] usb 1-1.3: Product: 802.11n WLAN Adapter
[  677.160167] usb 1-1.3: Manufacturer: Realtek
[  677.160184] usb 1-1.3: SerialNumber: 00e04c000001
[  678.414682] rtl8192cu 1-1.3:1.0 wlan1: renamed from wlan0
[  678.459963] systemd-udevd[728]: renamed network interface wlan0 to wlan1
Code:
airmon-ng pi:
PHY   Interface    Driver           Chipset
null     wlan1        rtl8192cu     Edimax Technology Co., Ltd EW-7811Un 802.11n [Realtek RTL8188CUS]
Code:
lsusb laptop
Bus 002 Device 007: ID 7392:7811 Edimax Technology Co., Ltd EW-7811Un 802.11n Wireless Adapter [Realtek RTL8188CUS]
Code:
dmesg laptop
[ 6028.369567] rtl8192cu: Chip version 0x10
[ 6028.402364] rtl8192cu: MAC address: 80:1f:02:e4:ca:af
[ 6028.402372] rtl8192cu: Board Type 0
[ 6028.402436] rtl_usb: rx_max_size 15360, rx_urb_num 8, in_ep 1
[ 6028.402484] rtl8192cu: Loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[ 6028.402846] ieee80211 phy2: Selected rate control algorithm 'rtl_rc'
[ 6028.403476] usb 2-7: firmware: direct-loading firmware rtlwifi/rtl8192cufw_TMSC.bin
[ 6028.416669] rtl8192cu 2-7:1.0 wlan2: renamed from wlan1
[ 6028.433877] rtl8192cu: MAC auto ON okay!
[ 6028.446173] rtl8192cu: Tx queue select: 0x05
Code:
airmon-ng laptop
PHY     Interface    Driver           Chipset
phy2     wlan2        rtl8192cu      Edimax Technology Co., Ltd EW-7811Un 802.11n [Realtek RTL8188CUS]
The dmesg output shows, that on my laptop the wifi adapter is listed as rtl819cu and the firmware rtlwifi/rtl8192cufw_TMSC.bin is loaded. On my pi the adapter is mostly listed just as usb-1.1.3 and the special firmware is not loaded. I checked the /lib/firmware/ folder and the rtlwifi/rtl8192cufw_TMSC.bin firmware file is present on the pi too, but the pi won't load it. Due to this fact airmon-ng won't find the phy interface on the pi.

So now I need my pi to recognize the wifi adapter and load the real firmware, but I couldn't find anything on the internet.