Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

This question already has an answer here:

I installed Lubuntu 14.04 on my wife's old netbook. I cannot get the wireless to work. I initially installed the STA driver, but it did not work. I then removed it and installed the b43 driver. Synaptic Package Manager shows that firmware-b43-lpphy-installer and b43-fwcutter are installed and that bcmwl-kernel-source is not installed.

Yet when I go to the Additional Drivers screen is says that Broadcom BCM4312 is not working and is using bcmwl-kernel-source (which I know is not installed). It also shows "unknown device" and gives me the option to continue using manually installed driver If I try to do so, nothing happens. There is also a grayed out option that says using non-free firmware for Linux kernel from linux-firmware-non-free.

Any help would be appreciated. I am at my wits end, and the wife is threatening to go buy a Windows computer.

OK, it is not a blacklist issue. Here is the result of the dmesg | grep b43 command:

[17.652124] b43-phy0: Broadcom 4312 WLAN found (core revision 15)
[17.728574] b43-phy0: Found PHY: Analog 6, Type 5 (LP), Revision 1 
[22.268301] b43-phy0: Loading firmware version 478.104 (2008-07-01 00:50:23
share|improve this question

marked as duplicate by Luis Alvarado May 3 '14 at 16:12

This question was marked as an exact duplicate of an existing question.

If you simply removed bcmwl-kernel-source, it leaves behind a blacklist file that prevents the native driver b43 from loading. Let's remove it and see if we get your wireless working:

sudo rm /etc/modprobe.d/blacklist-bcm43.conf
sudo modprobe b43

Is your wireless now working? If not, try a reboot. If it is still not working, please edit your question to add the result of:

dmesg | grep b43

Please ignore 'Additional Drivers.' It installs the wrong driver for your device.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.