Disabling Bluetooth and WiFi

If you are running a Raspberry Pi as a server which is locked in a room or a cabinet somewhere, you don’t want to run the risk that someone could remotely access the device via Bluetooth or WiFi. So I would recommend you disable both of these features.

To disable WiFi and Bluetooth on a Raspberry Pi 4:

1. Edit /boot/config.txt as a system user and add the following:
   
   dtoverlay=disable-wifi
dtoverlay=disable-bt
   
   into the file before the [pi4] section. This disables the Bluetooth and WiFi modules in the kernel.
2. Run the following to disable bluetooth daemon:
   
   sudo systemctl stop hciuart
sudo systemctl disable hciuart
3. Restart the Raspberry Pi