You could try this:
For BCM4306/3, BCM4311, BCM4318, BCM4321, BCM4322 (only 14e4:432b), BCM4312 (with Low-Power):wget https://ftp.linux.it/debian/pool/contrib/b/b43-fwcutter/firmware-b43-installer_019-4_all.deb
...or for BCM4301, BCM4306/2, BCM4306:
wget https://ftp.linux.it/debian/pool/contrib/b/b43-fwcutter/firmware-b43legacy-installer_019-4_all.deb
Install:
dpkg -i firmware-b43*
...if necessary with the option "--force-all".