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.

If this helps u:

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Hi 😄

If you do:

sudo reged -x "<WINDOWS_MOUNTPOINT>/Windows/System32/config/SYSTEM" "HKEY_LOCAL_MACHINE\SYSTEM" "\ControlSet001\Services\BTHPORT\Parameters\Keys" "/tmp/bt_keys.reg"

reged (it's part of chntpw) will export the bluetooth pairing keys in a file that you can simply cat:

cat "/tmp/bt_keys.reg"

and that will give:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BTHPORT\Parameters\Keys]

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BTHPORT\Parameters\Keys\00f48d9e41aa]
"34885dd82480"=hex:BE,7F,B1,99,23,29,D5,B2,6A,E2,F6,96,2E,FD,16,8A

00f48d9e41aa is the bluetooth controller MAC (what you call Unique id)
34885dd82480 is the bluetooth device MAC
BE,7F,B1,99,23,29,D5,B2,6A,E2,F6,96,2E,FD,16,8A is the pairing key

With this method you can skip most of the steps here. Just copy the key and paste it (without commas obviously) in the relative info file, in this case is:
/var/lib/bluetooth/00:F4:8D:9E:41:AA/34:88:5D:D8:24:80/info

Moreover, with having that exported reg file, you can automate the whole process with a simple script.
Take a look here https://github.com/KeyofBlueS/bt-keys-sync

Regards 👍

@KeyofBlueS , your comment was really useful. I followed the original instructions unsuccessfully as I have 2 different bluetooth receivers (only one in use) and for some reason I was getting an incorrect pairing key. With the registry file itself I was able to identify both pairing keys and use the right one in the Linux config. Thank you very much!

@IgorRodriguez It’s a pleasure

@Nielius I tried this on Linux Mint 21.1 (Equivalent to Ubuntu 22.04) and this did not work. My Link Key came from Windows 11. I don't have an option for the [LinkKey] entry on my 'info' file either. Any work arounds?

an easy solution for this, change bluetooth mac address on linux

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

now you have a new identity on linux. pair with your device, note you have to do this on every restart.
now when you return to windows you won't need to pair again.

@Nielius I tried this on Linux Mint 21.1 (Equivalent to Ubuntu 22.04) and this did not work. My Link Key came from Windows 11. I don't have an option for the [LinkKey] entry on my 'info' file either. Any work arounds?

I have Windows 11 - Ubuntu 22.04 Dual Boot System.
This instructions didn`t work for me for the first few times. But I reset my Bluetooth device, repeated the steps and it worked.
Also try to modify key for your bluetooth device using this steps:

• Enter sudo mode using this command: sudo su -
• Go to /var/lib/bluetooth/ using this command: cd /var/lib/bluetooth/
• Chose your bluetooth module using unique id: cd [Unique ID]
• Look through paired bluetooth devices(using "ls" command) and chose one that you need using this command: cd [Mac Address]
• Enter "vim info" and hit enter
• Modify your bluetooth device key using vim(take one from Windows as explained up above and switch with one that already here)
• Save and close Vim
• Not exiting sudo mode enter this command: sudo service bluetooth restart

Screenshot with most of commands attached below.

Thanks so much guys, this helped a lot

@bjoern-vh
I experienced something similar with 2 different Logitech keyboards:

Node has 0 subkeys and 11 values
  size     type              value name             [value if type DWORD]
    16  3 REG_BINARY         <LTK>
     4  4 REG_DWORD          <KeyLength>               16 [0x10]
     8  b REG_QWORD          <ERand>
     4  4 REG_DWORD          <EDIV>                 51860 [0xca94]
    16  3 REG_BINARY         <IRK>
     8  b REG_QWORD          <Address>
     4  4 REG_DWORD          <AddressType>              1 [0x1]
    16  3 REG_BINARY         <CSRK>
     4  4 REG_DWORD          <OutboundSignCounter>      0 [0x0]
     4  4 REG_DWORD          <MasterIRKStatus>          1 [0x1]
     4  4 REG_DWORD          <AuthReq>                 45 [0x2d]

I don't understand the problem and appreciate any support :-)

I did find a solution. Looks like each time you pair a keyboard like that, there are two differences when compared to @madkoding instructions:

1. Each time the keyboard gets paired, it gets a new MAC address (don't know whether it's a simple increment or a limited pool of addresses)
2. You need to migrate at least two keys (you have three: LTK, IRK and CSRK, but mine doesn't have the latter)

What I did was:

1. Pair your device in Linux, reboot to Windows
2. Pair it in Windows, reboot to Linux
3. Find the device entry using chntpw like you already did and save the keys in HEX format: hex LTK, hex IRK and hex CSRK (and remove the separating spaces between the bytes)
4. Change saved Linux bluetooth device MAC address to match Windows one (in my case the difference was in the final hex digit): just rename /var/lib/bluetooth/<bt adapter mac>/<device mac>, in the quote above it should be changed to D8:37:79:92:51:BE.
5. Change the keys in /var/lib/bluetooth/<bt adapter mac>/<new device mac>/info. Just compare Windows registry keys abbreviation to keys names from info, for me it was:

IRK:
[IdentityResolvingKey]
Key=...

LTK:
[PeripheralLongTermKey]
Key=...

And, it should then work after a reboot, or sudo service bluetooth restart. In my case, on Kubuntu 23.04, the system was glitching and crashing a lot after the bluetooth service restart, not sure what happened, but a reboot cured it.

Updated instructions... i'm no longer testing it, but i'll still receive the recommendations from other users to update this gist

I successfully copied Windows 11 key to Debian 12. Thanks for the guide.

I'm on Windows 11 and Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BTHPORT\Parameters\Keys is empty. But I have a paired mouse in W11. Any idea where the key is stored?

I'm on Windows 11 and Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\BTHPORT\Parameters\Keys is empty. But I have a paired mouse in W11. Any idea where the key is stored?

This is the solution: https://superuser.com/questions/1677881/bluetooth-pairing-on-dual-boot-of-windows-11-linux-or-some-os-else

I just successfully paired the keyboard this morning, then a sleep mode occurred when I returned from work and the keyboard wont pair with Ubuntu anymore, although I double checked the linking key harmonization is correct with Windows. Any idea why this might have happened?

@ForestEco Sleep mode usually have trouble with some bluetooth-wifi. Check your bluetooth model. If your notebook not fully support, check for experimental drivers or replace the wifi-bluetooth module with some other compatible like Intel AX

It worked, thank you!
In case someone runs into the same issues as me:

Note the MAC address of the device for later steps.

I couldn't find a tutorial for Windows 11.
You can find the mac address under:
device manager -> bluetooth -> right click the desired device -> properties -> details -> in the list scroll to "bluetooth device address"

Use chntpw to Access Registry

If chntpw SYSTEM is supposed to open a new console then it didn't happen for me. But the command shared by @KeyofBlueS works (remove the commas!)

Am I the only one for whom this doesn't work.
PS : Followed all the steps.

Am I out of luck if my Windows partition is encrypted?

@akaihola if you can mount it on Linux, it's fine, otherwise bad luck

The guide also shows how to change the bluetooth mac address on Linux if necessary. Is this something that would solve the need to re-pair my headset whenever booting to the other OS?

Windows 11 / Ubuntu 24.04

Mouse with Bluetooth 5.0 LE

I end up doing the reverse of this method to get it to work.
I tried copying the Long Term Key values from Windows to Linux, but that didn't work
but doing the reverse worked!

Here’s how you can do it:

First, Remove the current pairing of your mouse in Linux and pair it again.
Then, Note down the new MAC address and Long Term Key values, which you can find in \var\lib\bluetooth\...\{mac-address}\info

Now, reboot into Windows.

To modify the Bluetooth registry keys in Windows, you'll first need permission. Follow these steps:
1. Open the Registry Editor and navigate to ...\ControlSet001\Services\BTHPORT\Parameters\Keys
2. Right-click on the Keys folder, select 'Permissions', and add your Windows user. Grant it 'Full Control' permissions.
3. Relaunch Registry Editor

Next, rename the MAC address key of your mouse to match the one used in Linux (\var\lib\bluetooth\...\{mac-address})

(Keep the formatting as it is in Windows)
...\ControlSet001\Services\BTHPORT\Parameters\Keys\...\{mac-address}
...\ControlSet001\Services\BTHPORT\Parameters\Devices\{mac-address}

Then, navigate to ...\Keys\...\{mac-address}
and modify the LTK, ERand, and EDIV key values to match the corresponding Long Term Key values

After making these changes, restart your computer.

That’s it! Your setup should now be complete.

This method may not work with all devices, I'm having an issue with a Bluetooth 5.2 HeadPhone
When I pair it with Windows I can't find any key for the HeadPhone in ...\Parameters\Keys\...\
even with permission.

7. Find and Copy the Pairing Key
   ...
   Retrieve the pairing key (hex code) associated with your device.

Note that you need some additional steps here to retrieve the correct key.

here is what you need to do:

ls
Node has 1 subkeys and 0 values
key name
<keyid>

cd <keyid>

ls
Node has 0 subkeys and 1 values
size type value name [value if type DWORD]
16 3 REG_BINARY <regid>

hex <regid>
Value <regid> of type REG_BINARY (3), data length 16 [0x10]
:00000 XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX XX.......aU..'..

copy paste 17 hex number
remove spaces

key is in format
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX (34 letters)

add this to [LinkKey] section

Windows 11 / Ubuntu 24.04

Mouse with Bluetooth 5.0 LE

I end up doing the reverse of this method to get it to work. I tried copying the Long Term Key values from Windows to Linux, but that didn't work but doing the reverse worked!

Here’s how you can do it:

First, Remove the current pairing of your mouse in Linux and pair it again. Then, Note down the new MAC address and Long Term Key values, which you can find in \var\lib\bluetooth...{mac-address}\info

Now, reboot into Windows.

To modify the Bluetooth registry keys in Windows, you'll first need permission. Follow these steps: 1. Open the Registry Editor and navigate to ...\ControlSet001\Services\BTHPORT\Parameters\Keys 2. Right-click on the Keys folder, select 'Permissions', and add your Windows user. Grant it 'Full Control' permissions. 3. Relaunch Registry Editor

Next, rename the MAC address key of your mouse to match the one used in Linux (\var\lib\bluetooth...{mac-address})

(Keep the formatting as it is in Windows) ...\ControlSet001\Services\BTHPORT\Parameters\Keys...{mac-address} ...\ControlSet001\Services\BTHPORT\Parameters\Devices{mac-address}

Then, navigate to ...\Keys...{mac-address} and modify the LTK, ERand, and EDIV key values to match the corresponding Long Term Key values

After making these changes, restart your computer.

That’s it! Your setup should now be complete.

This method may not work with all devices, I'm having an issue with a Bluetooth 5.2 HeadPhone When I pair it with Windows I can't find any key for the HeadPhone in ...\Parameters\Keys...\ even with permission.

Windows 11 / Ubuntu 24.04

Mouse with Bluetooth 5.0 LE

I end up doing the reverse of this method to get it to work. I tried copying the Long Term Key values from Windows to Linux, but that didn't work but doing the reverse worked!

Here’s how you can do it:

First, Remove the current pairing of your mouse in Linux and pair it again. Then, Note down the new MAC address and Long Term Key values, which you can find in \var\lib\bluetooth...{mac-address}\info

Now, reboot into Windows.

To modify the Bluetooth registry keys in Windows, you'll first need permission. Follow these steps: 1. Open the Registry Editor and navigate to ...\ControlSet001\Services\BTHPORT\Parameters\Keys 2. Right-click on the Keys folder, select 'Permissions', and add your Windows user. Grant it 'Full Control' permissions. 3. Relaunch Registry Editor

Next, rename the MAC address key of your mouse to match the one used in Linux (\var\lib\bluetooth...{mac-address})

(Keep the formatting as it is in Windows) ...\ControlSet001\Services\BTHPORT\Parameters\Keys...{mac-address} ...\ControlSet001\Services\BTHPORT\Parameters\Devices{mac-address}

Then, navigate to ...\Keys...{mac-address} and modify the LTK, ERand, and EDIV key values to match the corresponding Long Term Key values

After making these changes, restart your computer.

That’s it! Your setup should now be complete.

This method may not work with all devices, I'm having an issue with a Bluetooth 5.2 HeadPhone When I pair it with Windows I can't find any key for the HeadPhone in ...\Parameters\Keys...\ even with permission.

Hi, also need to change other values, if maybe it doesn't work....

I dit it as you did, by this reverse way, but it didn't works.

So, I also change the

• IRK (IdentityResolvingKey) from Linux
• Address Value, on Keys windows. So the value from linux shoul be change 3 times
  1 --> \ControlSet001\Services\BTHPORT\Parameters\Keys...{mac-address}
  2 --> \ControlSet001\Services\BTHPORT\Parameters\Devices{mac-address}
  3 --> \ControlSet001\Services\BTHPORT\Parameters\Keys...{mac-address}\Address (Here change the value os this QWORD)

That works for me......................👍👍👍👍

This is just a memo to pair a nice!nano v2 (like the board of Typeractive's Lily 58) on both Win11 and Ubuntu 22.04 simultaneously.

Prerequisites:

• Follow up to Step 7 above.

8. Edit the Bluetooth file for your device

• Edit the corresponding file in your Ubuntu:

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

• Replace the Keys of PeripheralLongTermKey and SlaveLongTermKey with the upper-cased hex value of LTK in the device registry, or appearing in the .reg exported with KeyofBlueS's method.
• Add [IdentityResolvingKey] and set Key at the upper-cased hex value of CentralIRK in the device registry like:

[IdentityResolvingKey]
Key=YOUR_UPPER_CASED_CENTRAL_IRK

9. Restart Bluetooth service

• Save the changes and restart the Bluetooth service:

sudo service bluetooth restart

I still have issue with my Microsoft Bluetooth Ergonomic Mouse. This one is really tricky.
Yes it can pair with up to 3 device, but if I pair it on both OS on my dual boot (Windows 11, LMDE 6), the mouse with always delete the older pairing because it's the same MAC address. So everytime I boot the other OS, I have to pair the device again and lose all preferences.

First, it's one of them changing MAC Address between each pairing because why not. That I can manage.
On Linux, I got 3 keys: [LongTermKey], [PeripheralLongTermKey]and [SlavelLongTermKey]. The two last ones are identical but the first one differs.
On Windows, only one key stamped as LTK. I got also ERand and EDiv but no IRK or CRK, even though there is a CEntralIRKStatus with a value of 1.

I never got a working combination. The best issue I got was to remove [LongTermKey] entirely and leave the two last ones with values I copied from Windows. After that, I got a stable connection on Linux (whereas all other tries resulted in connecting/disconnecting because key seemed wrong) but the mouse is blinking saying there is no connection.

Any ideas how to do on this one?

I still have issue with my Microsoft Bluetooth Ergonomic Mouse. This one is really tricky. Yes it can pair with up to 3 device, but if I pair it on both OS on my dual boot (Windows 11, LMDE 6), the mouse with always delete the older pairing because it's the same MAC address. So everytime I boot the other OS, I have to pair the device again and lose all preferences.

First, it's one of them changing MAC Address between each pairing because why not. That I can manage. On Linux, I got 3 keys: [LongTermKey], [PeripheralLongTermKey]and [SlavelLongTermKey]. The two last ones are identical but the first one differs. On Windows, only one key stamped as LTK. I got also ERand and EDiv but no IRK or CRK, even though there is a CEntralIRKStatus with a value of 1.

I never got a working combination. The best issue I got was to remove [LongTermKey] entirely and leave the two last ones with values I copied from Windows. After that, I got a stable connection on Linux (whereas all other tries resulted in connecting/disconnecting because key seemed wrong) but the mouse is blinking saying there is no connection.

Any ideas how to do on this one?

I was finally able to get my Microsoft Explorer Mouse and Designer Compact Keyboard working, by some better guidance in this post
https://unix.stackexchange.com/a/413831. I had a similar experience to you, where mouse would connect then disconnect in a loop.

Important

1. MAC changes on device repairing, and it's easy to miss if you're only visually looking at the begin and end of a MAC entry. So make sure you rename the directory
2. With my Win11 and Microsoft devices, IRK is set in registry root folder level of Parameters\Keys\{Bluetooth-Controller-ID}' called CentralIRK. I used this value for setting any [IdentityResolvingKey] that's used for all the devices using this same Bluetooth Controller. Not sure if this was necessary, but I also added a [LocalSignatureKey] with this same value.
3. Especially for my MS mouse, the only other section I needed was [LongTermKey], and it was extremely important to get the Rand and EDiv values byte-aligned as mentioned in the post. MS Designer Compact Keyboard did not care about these values.
4. I deleted the other key sections, I can't say whether they are necessary in the longer term, but for now this is working for me

That's what was missing! I was missing the CentralIRK in the root folder level. I also got another key in that folder with an hex name but idk what it is for.
I had to add the [IdentityResolvingKey] section in info and delete the other useless one.

Now it works as well. Thanks!

Hello, my \ControlSet001\Services\BTHPORT\Parameters\Keys[Mac Address] is empty, what can I do ?

@Nielius I tried this on Linux Mint 21.1 (Equivalent to Ubuntu 22.04) and this did not work. My Link Key came from Windows 11. I don't have an option for the [LinkKey] entry on my 'info' file either. Any work arounds?

I have Windows 11 - Ubuntu 22.04 Dual Boot System. This instructions didn`t work for me for the first few times. But I reset my Bluetooth device, repeated the steps and it worked. Also try to modify key for your bluetooth device using this steps:

• Enter sudo mode using this command: sudo su -
• Go to /var/lib/bluetooth/ using this command: cd /var/lib/bluetooth/
• Chose your bluetooth module using unique id: cd [Unique ID]
• Look through paired bluetooth devices(using "ls" command) and chose one that you need using this command: cd [Mac Address]
• Enter "vim info" and hit enter
• Modify your bluetooth device key using vim(take one from Windows as explained up above and switch with one that already here)
• Save and close Vim
• Not exiting sudo mode enter this command: sudo service bluetooth restart

Screenshot with most of commands attached below.

Thank you for the additional explanation. Only in "sudo su - " mode, it is possible to edit the contents inside [Unique ID], otherwises those files are "permission denied" and thus cannot be edited.

sudo reged -x "<WINDOWS_MOUNTPOINT>/Windows/System32/config/SYSTEM" "HKEY_LOCAL_MACHINE\SYSTEM" "\ControlSet001\Services\BTHPORT\Parameters\Keys" "/tmp/bt_keys.reg"

Above, a comment has mentioned,
sudo reged -x "<WINDOWS_MOUNTPOINT>/Windows/System32/config/SYSTEM" "HKEY_LOCAL_MACHINE\SYSTEM" "\ControlSet001\Services\BTHPORT\Parameters\Keys" "/tmp/bt_keys.reg"
This will put everything into the file. Then read it using cat /tmp/bt_keys.reg.
I just completed the setup, works well.

It half worked for me, now my linux install can ALWAYS connect, but my windows 11 need to forget and connect again every time, does anyone know how can this be solved?