Unblock disabled wireless card in Ubuntu

I have got broadcom wireless card installed in my Ubuntu Box and it works fine. But lately I found a very strange problem. All of a sudden, It stopped working. I mean I couldn’t turn it on anyway, It always appeared as disabled. I tried uninstalling the driver and re-install of the driver, it seemed to work fine as long as I re-installed the driver but after I restart the Laptop. The problem re-appear. Then After few hours of google and digging through forums I found a solution. The simplest solution I have found is to use “rfkill” program and unblock the wifi card.

If you want to have quick look on the commands used, they are here in the screenshot.

At first install the rfkill program
[sourcecode language=’bash’]$ sudo apt-get install rfkill[/sourcecode]

Then at first list your wifi driver, with the command
[sourcecode language=’bash’]$ sudo rfkill list[/sourcecode]

The above command will list your available wifi cards with their status
0: brcmwl-0: Wireless LAN
Soft blocked: no
Hard blocked: yes
1: hp-wifi: Wireless LAN
Soft blocked: no
Hard blocked: no

Look for line Hard blocked: yes, in above case its “0: brcmwl-0: Wireless LAN”, brcmwl is the broadcom wireless driver. We are interested in the Index that is 0 (zero).

Now, use the below command to unblock the wifi, we use 0 (zero) index and supply as parameter to unblock.
[sourcecode language=’bash’]$ sudo rfkill unblock 0[/sourcecode]

Now, to confirm that our wifi actually has been unblocked, we can again use the previous “sudo rfkill list” command.
[sourcecode language=’bash’]$ sudo rfkill list[/sourcecode]

This time output should be something like
0: brcmwl-0: Wireless LAN
Soft blocked: no
Hard blocked: no
1: hp-wifi: Wireless LAN
Soft blocked: no
Hard blocked: no

See, there is no “Hard blocked: yes” line. This means the wifi has been unblocked and can be used as regular.

I have found that the index keeps changing and doesn’t remain the same, so next time you get the problem, you will need to repeat the steps from the “$ sudo rfkill list”.

If this doesn’t solve your problem, then you might want to follow other solutions given in the link below.
1. http://askubuntu.com/questions/9816/wireless-shows-up-as-disabled-how-can-i-get-it-working
2. http://pkadetiloye.blogspot.com/2010/11/ubuntu-wireless-disabled-siocsifflags.html