I use BT4-Final and a T410. When I enter

airmon.sh start wlan0

BT show:

Intel 4965/5xxx iwlagn - [phy0]iwlagn 0000:03:00.0: iwlwifi-6000-2.ucode firmware file req faild: -2
iwlagn 0000:03:00.0: iwlwifi-6000-1.ucode firmware file req failed: -2
iwlagn 0000:03:00.0: Could not read microcode: -2
SIOCSIFFLAGS: No such file or directory

I don't find the files.

Intel® Wireless WiFi Link drivers for Linux*

just offer 4.ucode