bluetooth-dual-boot

This will help you to setup a bluetooth device in dual boot: Linux (Ubuntu 21.04) and Windows 10 without having to pair it on every boot. If you have more than one BT device could be useful to prior remove them all and then add them one by one.

1. Pair it in Ubuntu, reboot.
2. Pair it on Windows. Yes, this will remove the paring in Ubuntu, just carry on.
3. Now in Windows, run bt_key.bat as Administrator, this will generate the file c:\win_keys.txt, you'll need this file in Ubuntu, move it if you need to, it will look like this:

Windows Registry Editor Version 5.00

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

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\BTHPORT\Parameters\Keys\[adaptor mac]]
"MasterIRK"=hex:9e,35,be,a6,81,01,9b,bb,e0,e7,30,17,a6,18,8c,79

[HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\services\BTHPORT\Parameters\Keys\[adaptor mac]\[windows device mac]]
"LTK"=hex:af,ba,0b,39,32,66,c0,cc,17,b6,dc,da,cc,4f,7e,1f
"KeyLength"=dword:00000010
"ERand"=hex(b):20,dd,df,fa,77,9a,67,12
"EDIV"=dword:0000f314
"IRK"=hex:4f,d5,a1,5a,43,c2,9f,d4,7f,e0,43,ad,8a,af,3b,27
"Address"=hex(b):c4,ca,10,b9,c6,ed,00,00
"AddressType"=dword:00000001
"MasterIRKStatus"=dword:00000001
"AuthReq"=dword:0000002d

4. Power off the bluetooth device.
5. Now boot to Ubuntu, you can disable the Bluetooth if you want to.
6. Edit the ubuntu_keys.py script, replace the mock values with the ones generated in win_keys.txt. For example:

LTK = "af,ba,0b,39,32,66,c0,cc,17,b6,dc,da,cc,4f,5e,1f"
KeyLength = "00000010"
ERand = "20,dd,df,fa,77,9a,67,11"
EDIV = "0000f374"
IRK = "4f,d5,a1,5a,43,c2,9f,d4,7f,e0,43,ad,8a,af,3b,27"

6. Open a Terminal and run the script python ubuntu_keys.py. If you need to install Python, use this command sudo apt-get install python. This will output something like this:

[IdentityResolvingKey]
Key=4FD5A15A43C29FD47FE043AD8AAF3B27

[LongTermKey]
Key=AFBA0B393266C0CC17B6DCDACC4F5E1F
Authenticated=0
EncSize=16
EDiv=62324
Rand=1254140861346733344

7. Use this printed values to replace the ones in the info file located in /var/lib/bluetooth/[adaptor mac]/[linux device mac]/
8. Rename the [linux device mac] to match the [windows device mac], use uppercase. i.g. mv AA:AB:AC:AD:AF:B0 AA:AB:AC:AD:AF:B1
9. Reboot to Ubuntu. Enjoy!