Lenovo Yoga3 Pro wifi driver does not work

  1. Turn off the secure boot

  2. Remove bcmwl-kernel-source:

    sudo apt purge bcmwl-kernel-source
    
  3. Re-install bcmwl-kernel-source:

    sudo apt-get update
    sudo apt-get install bcmwl-kernel-source
    
  4. Reboot. Your wireless should now be working.

Check this link for more information.