Until now my wlan has been working perfectly on a two week old 14.04 install on a brand new E540. It suddenly died on me, couldn't be turned on in settings > networks or via Fn + F8.
rfkill
output:
~$ rfkill list all
0: hci0: Bluetooth
Soft blocked: no
Hard blocked: no
1: tpacpi_bluetooth_sw: Bluetooth
Soft blocked: no
Hard blocked: no
2: tpacpi_wwan_sw: Wireless WAN
Soft blocked: no
Hard blocked: no
3: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
Fn + F8 only toggles the soft block, same for rfkill unblock all
I'm in need of any method of toggling the hard block on the phy0 Wireless Lan.
Best Answer
I stumbled on the solution from a friend who had a similar issue on an old Dell inspiron. The E540, and probably similar Thinkpad models, automatically turns off the wireless card when an ethernet cable/ usb modem is connected before boot. This functionality is fine for Windows where Fn + F8 actually toggles the hard block, but on linux it requires a restart with any LAN connections removed.
So the solution for now is to only connect my 3G modem after boot.
Update:
If anyone knows how to toggle hard blocked network connections in linux, please to add an answer, this is really just an interim solution that doesn't fix the underlying issue.