A small note to this old topic.
Broadcom has published proprietary (closed source) Debian drivers for their Wifi cards.
In LL, you can install it from Settings Install Drivers.
I don't know about Windows but since those drivers are in Debian package, there should
be a way to install them to other Linux brands too
However, if the open source bcm43xx works, then I don't recommend to install the closed source drivers
Broadcom has published proprietary (closed source) Debian drivers for their Wifi cards.
In LL, you can install it from Settings Install Drivers.
I don't know about Windows but since those drivers are in Debian package, there should
be a way to install them to other Linux brands too
However, if the open source bcm43xx works, then I don't recommend to install the closed source drivers