reference/WirelessOnMacbookAir.md

1. Purge the broken driver

$sudo apt purge bcmwl-kernel-source broadcom-sta-dkms

2. Install the necessary Linux headers

$sudo apt update
$sudo apt install linux-headers-$(uname -r)

3. Install the correct firmware and package

$sudo apt install firmware-b43-installer broadcom-sta-dkms

4. Reboot