Pairing bluetooth devices in dual boot with Linux Ubuntu and Windows 10/11

pair-dual-boot-bluetooth.md

Pairing Bluetooth Devices in Dual Boot with Linux Ubuntu and Windows 10/11

Introduction

This guide provides updated instructions for pairing Bluetooth devices (such as keyboards or mice) in a dual-boot environment with Linux Ubuntu and Windows 10/11, incorporating community feedback and suggestions.

Instructions

1. Pair in Linux First

• Pair your Bluetooth device in Linux. This is crucial to ensure the LinkKey remains consistent.
• Note: Do not re-pair the device in Linux after completing the pairing in Windows.

2. Pair in Windows

• Pair the Bluetooth device in Windows. Note the MAC address of the device for later steps.

3. Install chntpw in Linux

• Install the chntpw package to read Windows registry keys:

  sudo apt-get install chntpw

4. Access Windows System Drive in Linux

• Mount your Windows system drive and navigate to the System32 config folder:

  cd /[MountedDrive]/Windows/System32/config

5. Use chntpw to Access Registry

• Execute the following command in the config folder:

  chntpw -e SYSTEM

6. Navigate to Bluetooth Registry Keys

• In the chntpw console, navigate to the Bluetooth registry keys:

  cd \ControlSet001\Services\BTHPORT\Parameters\Keys

7. Find and Copy the Pairing Key

• Use ls to list unique IDs and find your device's MAC address.
• Retrieve the pairing key (hex code) associated with your device.

8. Edit Linux Bluetooth File

• Edit the corresponding file in your Linux drive:

  sudo nano /var/lib/bluetooth/[Unique ID]/[Mac Address]/info

• Replace the Key value in the [LinkKey] section with the pairing key from Windows.
• If the [LinkKey] section is missing, add it manually.

9. Restart Bluetooth Service in Linux

• Save the changes and restart the Bluetooth service:

  sudo service bluetooth restart

Additional Methods and Tips

• Simplification with reged: Use reged to export Bluetooth pairing keys directly into a file for easier identification and copying.
• Bluetooth LE Devices: For Bluetooth LE devices, the data storage might differ. Users should research specific steps for these devices.
• Windows 11 Compatibility: This method is also compatible with Windows 11.
• Multiple Bluetooth Receivers: If you have multiple Bluetooth receivers, ensure you identify and use the correct pairing key.
• Changing Bluetooth MAC Address in Linux: If necessary, you can change the Bluetooth MAC address in Linux using the following commands:

  sudo hciconfig hci0 down
  sudo bluemoon -A
  sudo hciconfig hci0 up
  sudo systemctl restart bluetooth.service

• Adding Missing [LinkKey] Section: If the [LinkKey] section is missing in the info file, you should add it manually.

Acknowledgements

Special thanks to the community members who provided valuable insights and suggestions, including nnnnicholas, kna0085, lguangyu, KeyofBlueS, bjoern-vh, Nielius, IgorRodriguez, princeofguilty, and others.

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to retrieve the hex pairing key value of a given device, in step 7

Retrieve the pairing key (hex code) associated with your device.

in the chntpw console, use cat <the MAC address>

you will see some readable hex value and some non-readable char. like the following

(...)\BTHPORT\Parameters\Keys\700810a243d7> cat d8e2dff871b4
Value <d8e2dff871b4> of type REG_BINARY (3), data length 16 [0x10]
:00000  24 3F 2B 37 8B B5 49 FB BB CA B8 A2 0D F7 20 3A }&..Ks0.d..F._..

the first part of the 32 hex value is what you need, in this case '243F2B378BB549FBBBCAB8A20DF7203A' is the pairing key.