I\m having the same issues with a fresh install of BT4 pre final but the fix that worked for SL43R didn't help me out >&
iwconfig returns the following:
so i'm guessing its not an issue with the wlan adapter ... i got the ethernet link working fine as welllo no wireless extensions.
eth0 no wireless extensions.
usb0 no wireless extensions.
wmaster0 no wireless extensions.
wlan0 IEEE 802.11abgn ESSID:""
Mode:Managed Frequency:2.412 GHz Access Point: Not-Associated
Retry min limit:7 RTS thrff Fragment thr=2352 B
Link Quality:0 Signal level:0 Noise level:0
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
i'm on a Lenovo ThinkPad x200s if that helps