I just updated my Ubuntu 12.10 today and it went fine and I was told to restart system and after I restart my WiFi stopped working. Mine is Broadcom BCM4312 card . It was working fine just before the update, I tried reinstalling driver from software sources and it didn’t work, it shows the proprietary driver in use but network manager doesn’t detect my WiFi card.


5 Answers 5


I just fixed the issue, I found the kernel sources has not been installed which prevented from compiling the driver properly. So I installed kernel source for the current kernel from Synaptic then issued the following commands and my WiFi was instantly restored (like 3 or 5 seconds).

To install kernel headers and source:

 sudo apt-get install linux linux-headers-generic kernel-package

 sudo apt-get purge b43-fwcutter firmware-b43-installer firmware-b43-lpphy-installer firmware-b43legacy-installer bcmwl*

 sudo apt-get install b43-fwcutter firmware-b43-lpphy-installer bcmwl*

Then reboot.

This applies to BCM4312 only (My laptop is Lenovo g450)

For others can see this blog post, this might be useful for you.


I too had faced this issue. I connected it to wired lan and I again ran apt-get upgrade and restarted, then it started working.

I feel this is the worst installation upgrade from Ubuntu.

  • 3
    Indeed it does :(
    – faken
    Oct 25, 2012 at 22:16
sudo apt-get install bcmwl-kernel-source

I had same problem, with this everything will be fine.

If didn't install try first:

sudo apt-get remove bcmwl-kernel-source

Check /etc/resolv.conf I was also facing the same issue as loopback address was there as my DNS preference. If this is the case, then correct the dns address to resolve issue.


Go to Dash -> Software Sources -> Additional Drivers -> Using Broadcom 802.11 Linux ...

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