Issues with Ubuntu Karmic and Broadcom Wireless BCM4312 rev 01

If you’re having an issue where wireless connections are not available to you through network manager, or no networks show up, this method may resolve it for you. Note that this may work with other wireless cards as well.

First, identify your wireless card. At a terminal, type:

lspci | grep Broadcom

Look for output similar to the following:

03:00.0 Network controller: Broadcom Corporation BCM4312 802.11b/g (rev 01)

If your card matches, or you’re attempting this against another card, continue by making sure your system is completely up-to-date. Use Synaptic or Update Manager. (Both in System > Administration)

Next install the package linux-backports-modules-karmic. You will need a working wired connection for this.
At a terminal:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install linux-backports-modules-karmic

Try rebooting. If that doesn’t help at this point, continue by blocking the load of a few modules:

sudo echo "blacklist ssb" | sudo tee -a /etc/modprobe.d/blacklist-ssb.conf
sudo echo "blacklist wl" | sudo tee -a /etc/modprobe.d/blacklist-wl.conf

Reboot and test.

Note: If you want to roll-back this back at a future point, here’s the steps:

sudo echo "" > /etc/modprobe.d/blacklist-ssb.conf
sudo echo "" > /etc/modprobe.d/blacklist-wl.conf

(or simply delete the files)

I’m reposting from this site, where I originally found this fix. The site is very slow to load for me most days when I really need to refer back to it, as I’m sure others would love to as well, so I’m reposting here with some clarification and clean-up.

You might also want to read another post regarding Broadcom BCM4328 wireless problem in Ubuntu.

Did this work for you? Please leave your feedback in the comments.

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