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