[GUIDE] Enable VoLTE/VoWiFi on LineageOS 17.1 for EU carriers Oneplus 6T

[Sayonara123]

[GUIDE] Enable VoLTE + VoWiFi for German and other EU carriers on the Oneplus 6T running LineageOS 17.1

Requirements:

- Phone must be rooted
- A computer running Windows to connect your phone with (Also tested Windows 7 running in Virtualbox)
- Qualcomm USB Driver (Downloadlink)
- Qualcomm PST Tool (Downloadlink)
- ADB

IMPORTANT: This can break your phone! Make a backup of your EFS Partition! This can be done with TRWP.

1)
Download and install Qualcomm USB Driver and PST Tool on your computer. Make sure, you have the adb tool as well.

2)
On your phone activate the hidden developer settings:

Settings -> About -> Build-Number (press it multiple times)

then

Settings -> System -> Devloperoptions

Activate:
Android-Debugging
Local Shell

Connect your phone to your computer.

3)
Open a shell on your computer and type:

adb shell

Watch your phone to accept the incoming connection from your computer.

Type:

su

and watch your phone again to accept root access.

Activate the Diagnostic Mode by typing:

setprop sys.usb.config diag,serial_cdev,serial_tty,rmnet_ipa,mass_storage,adb

Your phone will disconnect from adb, but thats ok.

4)
On your computer open "PDC" from the installed QPST application as admin.
In the device list, select your phone.
In the upcoming list look for "Oversea-Commercial_DS", right click it and deactivate Sub0 and Sub1
Click "Oversea-Commercial_DS" again and press the Remove button.
Close the PDC Tool and open it again.
Select your phone again
Look for Telefonica_UK_Commercial, right click and SetSelectedConfig for both Sub0 and Sub1
Click on Telefonica_UK_Commercial again and click the Activate button
Close the application

5)
Unplug your phone and reboot it.
Make sure you have activated VoLTE/VoWiFI in your settings.

6)
No VoLTE/VoWIFI icon is shown in the status bar. You can check the IMS status as followed:
Open the dialer and enter the code: *#*#4636#*#*
This will open the Testing menu. Select the first entry "Phone information".
In the option "Select phone index" you can choose your sim card you want to get information about.
Then, press the three dotted menu in the upper right and select "IMS Service Status"
If it says "IMS Registration: Registered" everything is working fine. Depending on whether you are on WiFi or LTE, "Voice over LTE" or "Voice over WiFi" will be shown as "Available as well.

Enjoy!

 

[Termehansen]

Great work. I'm on Linux. What is this qpst and psd tools for exactly and is there a way to do the changes from Linux?

 

[Sayonara123]

Great work. I'm on Linux. What is this qpst and psd tools for exactly and is there a way to do the changes from Linux?

I'm on Linux too. Qpst is a USB Modem driver and PSD is a Tool to access and alter the modem firmware on the phone.
Unfortunately these will only run on Windows. I used VirtualBox and run Windows 7 (I bought a cheap license key some time ago) on it.

 

[Termehansen]

So none of these tools could be helpful?

https://github.com/openpst

 

[Sayonara123]

So none of these tools could be helpful?

https://github.com/openpst

Interesting, I didn't know these tools. Maybe it could work.

 

[martin.42]

Thank you for the guide. Still, I think you have a typo:

setprop sys.usb.config diag,serial_cdev,serial_tty,rmnet_ipa,mass_storage ,adb

There's a space preceding ',adb', and with blindly using this command something went wrong on my Windows PC. Had to restart. 'setprop' also supports only 2 arguments.

Another thing:

Remark:
I did not test it, yet. But you may have to repeat the procedure after every LineageOS update.

You should put that on top, maybe make it bold and set a bigger font. It looked like a tested and working method, I just blindly followed the instructions without questioning (also a mistake on my part).

Anyway, I followed the steps successfully but cannot see if VoLTE/VoWifi is functional as there is not indicator in LineageOS 17.1. If anyone knows a way, feel free to tell.
Thanks again.

 

[Sayonara123]

Thank you for your reply.

Thank you for the guide. Still, I think you have a typo:

You are right, It's a typo, I didn't notice. Fixed it.

Another thing:

The whole procedure was tested on my own phone. There was just one unclear thing, whether these changes survive an update of the LineageOS system. It does! So I removed this obsolet remark.

Anyway, I followed the steps successfully but cannot see if VoLTE/VoWifi is functional as there is not indicator in LineageOS 17.1. .

Yes, it's a pitty there's no indicator in the status bar. I've found another way to check functionality and added it to the guide.

Hope this make things more clearly.
Thx

 

[F5:ed]

Tried it on stock oos 10.3.6, and windows 10. Have swedish carrier Tre (Hallon).
Works great! Thanks for your guide! ?