How to change bluetooth device class

12.04 bluetooth

22,327

Solution 1

First, find your interface name:

hciconfig

It should give you the name of the interface, e.g., hci0.

Given that display your interface class:

hciconfig hci0 class

That should display your device class.

Finally, with super user privilege:

sudo hciconfig hci0 class 000408

should set up new class of your device.

A useful reference of bluetooth classes with hexadecimal and binary representations can be found here: http://www.question-defense.com/tools/class-of-device-bluetooth-cod-list-in-binary-and-hex

Solution 2

The BlueZ hostname plugin overrides the Name and Class settings in /etc/bluetooth/main.conf. Follow these steps to specify the Bluetooth Class of Device (CoD):

Skip loading the hostname plugin when starting the bluetooth daemon by modifying /lib/systemd/system/bluetooth.service. Example:
```
sudo sed -i 's/bluetoothd/bluetoothd \-\-noplugin=hostname/g' /lib/systemd/system/bluetooth.service
```

Alternatively you can specify an inclusion list using --plugin=<plugins>. See bluetoothd(8) and https://git.kernel.org/pub/scm/bluetooth/bluez.git/tree/plugins

Edit /etc/bluetooth/main.conf and specify Class in the General section. Specify Name as well if you want something other than BlueZ X.YZ:
```
[General]
Class = 0x1c0420
Name = UbuntuCarAudio
```
Reboot or restart the bluetooth service for the changes to take effect:
```
sudo systemctl daemon-reload
sudo service bluetooth restart
```
Verify the changes by running hciconfig -a or echo 'show' | bluetoothctl. hciconfig -a will show you the decoded Class of Device (CoD) information:
```
Name: 'UbuntuCarAudio'
Class: 0x1c0420
Service Classes: Rendering, Capturing, Object Transfer
Device Class: Audio/Video, Car Audio
```

Solution 3

You need to change class name in /etc/bluetooth/main.conf file.

Class = 0x00041C

Then restart bluetooth service

sudo service bluetooth restart

Then turn off your bluetooth from top panel icon and turn it on.

22,327

twinPrimesAreEz

Updated on September 18, 2022

Comments

twinPrimesAreEz over 1 year
I am trying to change my advertised bluetooth device class from computer to phone, running ubuntu 12.04. I downloaded the bluez sources and edited the main.conf file to change the line
```
Class = 0x000100 
```
to something else. I used
```
Class = 0x0c025a 
```
Then I ran make && make install. I think that works ok because the /etc/bluetooth/main.conf file has been updated with my changes.

Now, the problem is that when I actually try to connect to a device
```
hcitool cc <bdaddr>
```
I see that I am still advertising myself using the Class 0x000100 and not 0x0c025a.

What am I missing here to get this changes to take effect?
cfz42 over 5 years

Thanks for this detailed answer, while it does work fine for the Name, the Class doesn't get overridden anymore, instead it's set to 0x000000. Any idea what could cause this?
Chris Sidi over 5 years

@cfz42 I have seen the Service Classes bits get ignored, but I don't know what causes this - maybe BlueZ inspection of running services? You could try using hciconfig, e.g sudo hciconfig hci0 class 1c0420