Make Ubuntu Recognize Wifi Wireless Network Card

This is a problem for many users that install Ubuntu for the first time. Your Wifi will not work. You’ve tried everything to get Ubuntu to recognize your Wireless Network Card. You may have already tried this without success:

    sudo apt-get remove bcmwl-kernel-source
    sudo apt-get install firmware-b43-installer b43-fwcutter

The following fix will work if your Wireless Network controller ( 802.11b WLAN ) product is a “BCM” card by Broadcom Corporation. For example, “BCM4311” or “BCM43xx”.

On your terminal, run:

sudo lshw -C network

Find your Wifi card, which will look something like this:

description: Network controller
product: BCM4306 802.11b/g Wireless LAN Controller
vendor: Broadcom Corporation

Look underneath that for the “configuration:” line, which looks like this:

configuration: driver=wl latency=32

If the “driver” is set to “wl”, then that may be the entire problem. You must set it to use the “b43” driver instead of “wl”.

The Fix:

Make sure you are connected to the internet with a WIRED connection.

1. Run these commands (one at at time) from your terminal:

   
   sudo apt-get update
   
   sudo apt-get remove --purge bcmwl-kernel-source
   
   sudo apt-get install b43-fwcutter firmware-b43-installer
   
   echo "b43" | sudo tee -a /etc/modules
   
   sudo apt-get install linux-firmware-nonfree
   
   sudo apt-get install --reinstall linux-firmware-nonfree
   
   

2. Now we will edit the file blacklist.conf to remove 2 lines. First, open the file with this command:

   gksudo gedit /etc/modprobe.d/blacklist.conf

3. Now, in the gedit editor, remove the following configuration lines IF THEY EXIST EXACTLY LIKE THIS:

   blacklist b43
   blacklist b43legacy
   

4. SAVE the change to the /etc/modprobe.d/blacklist.conf file after removing the 2 lines.
5. REBOOT and retest wireless.

Source: https://answers.launchpad.net/ubuntu/+source/gnome-nettool/+question/225463