What Is Bluetooth HCI Snoop Log?

A Bluetooth HCI (Host Controller Interface) snoop log is a log file that contains all the Bluetooth transmissions that you have made on your Android gadget. Having this file means that you’ve got an app that allows logging (4.4) or which logs (Android 4.4) of all Bluetooth communications, your Android gadget logs Bluetooth usage automatically or you allow Bluetooth transmission logging.

What Is Bluetooth HCI Snoop Log

This is a storage of data of Bluetooth usage over time and hence should not be anything to be troubled about. It can even be deleted without a problem to clear the Bluetooth usage history on your device but it will be restored and updated with fresher Bluetooth use unless the logging of Bluetooth usage is disabled.

You should not worry about it since it is an ordinary feature from Android 4.4+.

Most Android devices are able to log full Bluetooth transmissions. Before Android 4.4 one required root and app such as Bluetooth HCI log. In all gadgets with Android developer settings, beginning with Android 4.4, the log choice is in existence.

How to create an HCI log

Enable developer settings.

The developer settings are usually invisible. Tapping on the builder number located in Android settings seven times will easily enable them.

Create log

Go to Android settings and open the developer menu. There is a checkbox identified “Enable Bluetooth HCI Snoop Log”. Before powering on the car, start the log and stop it before sending the file. This log file is stored in the SD storage or USB root and is known as btsnoop_hci.log.

Wireshark, a network protocol analyzer, can be used to peek into the file. You just need to retitle the file to *.cap and open it.

If you are a security specialist or a developer, sometimes you may want to analyze and capture the Bluetooth host controller interface packets. You will do this by enabling the Bluetooth HCI snoop log.

This will store these packets in a file on your device storage enabling easy retrieval. After that, you can use a program to analyze them for example Wireshark.

How to recover the HCI log

  • Go to settings on your Android device.
  • Click on developer options
  • Select Enable Bluetooth HCI snoop log.
  • Go back to settings on your device and then choose developer options
  • On the developer options window you then click on enable Bluetooth HCI snoop log.
  • This will enable your log file.
  • Turn off Bluetooth on your Android device.
  • Turn Bluetooth ON.
  • Restart or reboot your Android device.

Once this procedure is complete, your device is able to generate the HCI log file and save it to /sdcard/btsnoop_hci.log.

When retrieving the HCI log from the Android device you have two options.

a) You can connect your Android device to a computer. The file will be located in one of the drives that are mountable. Copy this file from here to C:/Users/Public/Public Documents/Frontline Test Equipment/My Capture File/.

b) You also have another option of using the Android debugging bridge which can is found in the kit of the software developer.

The procedure for this option is:

  • Select USB or Android debugging on the development screen.
  • Connect your device to the computer using a USB cable.
  • On your computer open a terminal and run ‘adb devices’ command.
  • You should be able to see your Android device on this list confirming that ADB works.
  • In the terminal, copy ‘adb pull /sdcard/btsnoop_hci.log’ to the computer.

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