VoWiFi with UK MVNO on Pixel 4 ?

Cancunia

Does anyone know if VoWiFi will work on the P4 running Graphene with a UK MVNO?

I have tried 4 different UK MVNOs without success, all say that they are 'waiting for Google' to do something but have had no response. I don't know if this is a hardware issue or Android related.

I've looked at the Graphene Usage Guide but can't see anything one way or the other.

Thanks

flawedworld

If it works on the stock OS it should work on GrapheneOS.

Cancunia

Well, that's the problem. It does not work on the stock OS (Android 12) with any UK MVNOs but it does work on MNOs such as Three & Vodafone. I have no idea why and hoped that someone in the Graphene universe might know why, or, if it will work with Graphene as opposed to Android.

Cancunia

Pardon my ignorance, I'm new here!
Just noticed the 'solved' tag. I'm not sure if that means no one will respond any more, so thought I'd ask if anyone has more details on how Graphene handles VoWiFi. For example if it is different from how Android works in this respect or is it that Graphene uses the same code base?

Hulk

If it does not work on Stock OS, it will not work on GrapheneOS.

Please read this part of the official usage guide:
https://grapheneos.org/usage#carrier-functionality

GrapheneOS is based on Android Open Source Project.
This page provides an overview of currently implemented features differentiating GrapheneOS from AOSP:
https://grapheneos.org/features

Cancunia

Many thanks for that clarification. I was hoping that the MVNO issue was somehow due to a restriction in the official Android OS that may have been stripped out by, or simply not included in GrapheneOS.
It's an odd situation where VoWiFi works fine on the parent MNO carrier, but not on the MVNO.
All the MVNOs that I have contacted with this issue, tell me that they're waiting for Google to do something, but no one has any further details of what or when.

Hulk

Cancunia

GrapheneOS includes bypasses for carrier restrictions on APN editing, tethering via USB, Ethernet, Bluetooth and Wi-Fi and the ability to disable 2G, actions which would not necessarily have been possible on the stock operating system.

Unfortunately VoWiFi is much more complicated and can't be "fixed" so easily.

Glad to be helpful :)

MetropleX

Just for posterity and anyone that may stumble across this thread as I've been searching for a possible resolution and definitive answer for you too the following places across the web are also where you've raised the issue:

https://support.google.com/pixelphone/thread/176141222/mvno-wifi-calling-on-pixel-phones-mvno-profile-downloads-incorrect?hl=en-GB

https://forum.xda-developers.com/t/do-google-need-to-enable-wifi-calling-for-every-network-mvno.4482253/

As for your main question there are the following:

A couple of resources for UK MNO and MVNO support:

https://www.simsherpa.com/networks/best-wifi-calling 19th April 2022
https://www.4g.co.uk/news/ee-o2-three-and-vodafone-which-networks-offer-wi-fi-calling/ 3rd June 2021
Slightly out of date as Lebara UK turned theirs on in June of this year:

https://mobile.lebara.com/gb/en/wifi-volte
To activate it on a Pixel 4:
https://deviceguides.vodafone.co.uk/google/pixel-4-android-10-0/calls-and-contacts/turn-wi-fi-calling-on-or-off/
To turn on Wi-Fi calling, you need to establish a connection to a Wi-Fi network and select 4G (LTE) as network mode.
Beyond that if it doesn't work it is definitely an MVNO issue if the combination of carrier settings and APN work to provide voice, text and mobile data.

Please let us know if any of the above helped and avoid duplicating the question across any further threads which will be deleted.

Cancunia

I agree totally about not duplicating so will try to answer more fully here than on the other thread I started that requests a carrier list.
I've spent a lot of time on this subject without getting clarity, in fact the first 2 links above are threads that I started. I have contacted 4 MVNOs about this issue, and each without exception, tells me the same thing, that it's something they are waiting for Google to action. So far, none have given any details of what that action is as I can't get past the First Line Support, except with ASDA, more on that later.
On the assumption that all the MVNOs might be correct as they're all saying the same thing, I initially thought that GrapheneOS might treat VoWiFI differently so I asked here too. From the answers on this thread I'm now understanding that Android & Graphene are more or less very similar if not exactly the same in regards to IMS / VoLTE/VoWifi. This means that there's no point in my trying to see if running Graphene on my P4 will solve the problem.
I am expecting a call from a support manager later this morning and will post what he tells me here.

Thanks again for the feedback so far, it's a lot more than I've had elsewhere.

MetropleX

Cancunia I know the first two links are you, same name see ;), I put them in here for anyone else who might stumble upon it in case you get the answer elsewhere but not update this thread should search it up. (Edited post for clarity.)

Have you tried the Lebara x Vodafone approach of being on wifi and enabling LTE only mode? I don't believe this is available on stock, but it is on GOS which may help you by flashing it.

Cancunia

MetropleX Have you tried the Lebara x Vodafone approach of being on wifi and enabling LTE only mode?

Thanks for updating the other post, makes more sense now. I'm fairly sure that VoLTE works as I can see it is provisioned in the Phone Info screens '##4636##' but as I live in a very poor signal area it's hard to be sure. Is there any more info you can share or link on 'Lebara x Vodafone'? It looks interesting.

MetropleX

Cancunia you don't need VoLTE to work for this VoWiFi enabling process, everything LTE is sent via data including calls which is why VoLTE is needed to use calls on 4G/LTE Only mode. What this will do when WiFi is connected is to try force the calls over WiFi enabling it in the process as the phone will attempt to provision it at that time going by their instructions.