Monday, October 24, 2016

Disable WIFI and Bluetooth on Raspberry Pi 3 Model B

Hardware: Raspberry Pi 3 Model B

Software: 2016-09-23 Raspbian Jessie Lite (minimal)

The Raspberry Pi 3 models are pretty powerful with lots of extras.  But when you start thinking about securing them and/or cutting down on power usage then it is time to start turning things off.

Here's how to shut down the WIFI and Bluetooth radios on the unit.

Log in to your RPi via SSH ( a local connection and then type in:

   sudo nano /etc/modprobe.d/raspi-blacklist.conf

If the file doesn't exist already then it will be created.  Add/edit the following lines to the file.  Any item with a # sign in front of it is remarked and not processed:


blacklist brcmfmac
blacklist brcmutil
blacklist btbcm
blacklist hci_uart

Hit CTRL-X, Y, then hit <Enter>.

Once this file is saved then rebooting your device will result in both of these radios being disabled. 

As a comparison, here are the results of running iwconfig from the command line prior to rebooting:

wlan0     IEEE 802.11bgn  ESSID:off/any
          Mode:Managed  Access Point: Not-Associated   Tx-Power=31 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:on

lo        no wireless extensions.

eth0      no wireless extensions.

And here are the results after editing the file above and executing a sudo reboot 0 command 

lo        no wireless extensions.

eth0      no wireless extensions.

As you can see, the wlan0 interface no longer exists because the WIFI chipset drivers were blocked from being loaded.  The same is true for the bluetooth drivers.

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