Great question — answering as the UphillTech team:
Please obtain a temporary internet connection, open a terminal and do: sudo apt-get update sudo apt-get purge bcmwl-kernel-source sudo apt-get install firmware-b43-installer Reboot and your wireless should be working. 'Additional Drivers' is incorrect for your 14e4:4315 device. If you have no internet capability, then do the purge step and then download this on some other computer: https://www.dropbox.com/s/7exlzch25ap6uha/b43.zip?dl=0 Transfer it on a USB or similar to your Ubuntu computer and drop it on your desktop. Right-click it and select 'Extract Here.' Now, in the terminal: sudo mkdir /lib/firmware/b43 sudo cp ~/Desktop/b43/* /lib/firmware/b43 Reboot.
Full answer by chili555: https://askubuntu.stackexchange.com/a/579493 (CC BY-SA 3.0).
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