The other day I installed Ubuntu on a notebook and noticed that there was no wireless driver available in the “Restricted Driver” manager program in Ubuntu. Switching to dmesg I noticed a message suggesting I download b43-fwcutter and follow the advice on a link to the broadcom firmware. That link suggested that when b43-fwcutter was downloaded it would take care of installing the broadcom firmware, a statement that turned out not to be true among Ubuntu and Lubuntu. There are actually two programs required:
The second program might be slightly different if you have an older broadcom firmware which requires firmware-b43legacy-installer instead of the firmware-b43-installer.
To install these type:
sudo apt-get install b43-fwcutter firmware-b43-installer
It’s the second command that does the fetching of the firmware. Without even restarting you should be up and going.