What's the best way to achieve this?

A Pixel 4a and Pixel 6 both running the latest O/S release and if I enter on the dialler "##0702##" I get different results: with the 4a nothing happens, but with the 6 it brings up IMS settings. And is this menu the best way of debugging Wi-Fi calling issues?

Ultimately I'd like to resolve an issue I'm experiencing with Wi-Fi calling on the Pixel 6, where it works fine with the physical SIM but not the eSIM. I can generate custom builds if need be, but first of all I'd like to understand where I should be looking. My carrier (Vodafone UK) doesn't use an app for provisioning settings and this is seemingly done via SMS and to start with I'd like to understand this process better, e.g. what does this do in practical terms and are settings persisted to the O/S somewhere or on the SIM.

    9600 have you tried the following from the eSIM?

    Try texting CALLING to 97888, you will get a text back to let you know WiFi calling will be added to the account.

    • 9600 replied to this.

      MetropleX Yes, tried that multiple times and spent hours with online support as they repeatedly resent settings. In the end we gave up and I had them transfer the line back to the physical SIM, at which point the WiFi calling toggle came back immediately.

      Presumably the network sends a "silent" SMS which configures some carrier settings? Can they be set any other way, e.g. via adb or the hidden IMS menu? Ideally I'd be able to save these while on the physical SIM, then re-apply after switch across again to eSIM.

        I'll be following this thread closely.
        Wifi calling (vodafone physical sim) worked perfectly when I first installed GOS but shortly after a GOS update wifi calling stopped working.
        I'm keen to find out how these settings are magically configured in the background too.

          timttmy Wifi calling (vodafone physical sim) worked perfectly when I first installed GOS but shortly after a GOS update wifi calling stopped working.

          Is this with a Pixel 6 also or another model?

            9600 can you try turning airplane mode on, then wifi back on, then trying to make a call with the eSIM number? Also confirm that the carrier settings listed for each SIM are the same.

            • 9600 replied to this.

              MetropleX I don't have an eSIM at present, as I had Vodafone transfer the number back to the physical SIM. However, when I did have the eSIM installed I couldn't make calls at home, where it had a good WiFi signal, but no cellular since it hadn't been provisioned on the 3G femto. Also there wasn't a WiFi calling setting as there was and is now with the line on the physical SIM.

              How do I confirm the carrier settings? Is this the "Operator settings version" string? I'm pretty sure it was the same as when on the physical SIM. I can switch the line back to eSIM again to confirm, but before I do this is there any way to get a dump of the IMS settings (as shown via the "##0702##" hidden menu) so that we can compare after the switch?

              16 days later

              So I managed to get this working, but this was after I'd had to do a factory reset and the WiFi calling toggle disappeared and would not come back no matter how many times support send OTA configuration (with the physical SIM this time). Feels like this OTA provisioning is really hit and miss. In any case, I got it working again by entering:

              *#*#0702#*#*

              Select 'SIMn Provisioned' and from that page edit the setting to enable the toggle in the settings for the SIM card in question, following which the WiFi calling will be visible.

              SIMn Provisioned

              IMS settings for SIM card

              The parameter is called VOICE_OVER_WIFI_SETTING_ENABLED and the value was changed from 0 to 1. Following which the toggle appeared.

              Is there no way to make this the default for both SIM slots?

              17 days later

              This is broken again after my Pixel 6 updated to TP1A.220905.004.2022090600 (possibly going from A12 to A13). The WiFi toggle disappeared and while I could still bring up the IMS Settings hidden menu, changes made there no longer persist across reboots and looks like they possibly don't work at all, since the toggle doesn't appear at all if I change the parameter as before.

                9600 what carrier settings are you on and what if anything changed in the APN? Is VoLTE working still? Has anything changed in the Phone Info pane provisioning wise *#*#4636#*#*? Have you checked the setting in the MyVodafone app is switched on?

                There is also another thread about issues with VoWiFi using an MVNO on Vodafone's back end . I wrote this:

                https://discuss.grapheneos.org/d/757-vowifi-with-uk-mvno-on-pixel-4/9

                After digging around further it seems Vodafone have an issue with this more than any other Carrier. So many examples of this from Vodafone users or their MVNOs like ASDA or Lebara et al

                • 9600 replied to this.

                  MetropleX Carrier settings are vodafone_gb-40000000331.54. The fundamental problem is that VoWiFi has never worked by default with this carrier, whereas it does if using stock with the same settings string. The workaround I found with A12 was to access IMS Settings via *#*#0702#*#*, select SIMn Provisioned, where n is the SIM in question, and then change the value for parameter VOICE_OVER_WIFI_SETTING_ENABLED from 0 to 1. This made the WiFi calling toggle appear and I could turn this feature on.

                  As of updating to A13, I can still make the IMS settings change, but it has no effect and if I reboot, I see that the value has reverted to 0. Hence it would seem that with this update you can no longer edit IMS settings from that menu. The best fix would obviously be for it to work by default, but failing this I was happy to go edit the parameter in IMS settings.

                  MetropleX Has anything changed in the Phone Info pane provisioning wise ##4636##?

                  Yes, neither VoLTE nor Wi-Fi calling are provisioned, as they were before the update.

                  MetropleX Have you checked the setting in the MyVodafone app is switched on?

                  Yes.

                  MetropleX So many examples of this from Vodafone users or their MVNOs like ASDA or Lebara et al

                  My understanding is that MVNOs operate their own IMS and so I could see this complicating matters, but I'm a Vodafone customer and not MVNO. The other data points being:

                  1. This worked fine — albeit with the manual config step for VoWiFi — prior to GOS update to A13.
                  2. My partner has the exact same handset and is running stock, same build version and carrier settings, and WiFi calling worked out-of-the-box, without the manual step I needed.