WiFi calling while abroad

[bige93]

Hi there! Just wanted to check what's your experience with using WiFi calling while outside of your home country.
I use T-Mobile PL and VoWiFi in not registered while in Germany. It works in Poland.
I tried with iPhone - WiFi calling connected right away.
Any similar experience?

Thanks!

[peixotorms]

did you try a polish vpn?

[bige93]

I didn't try that

[xantrk]

Same here. I am using dual SIM from different countries and neither of them connect to VoWIFI while roaming. I am sure at least one of them allows this. VPN doesn't do anything either.

[xantrk]

Same here. I am using dual SIM from different countries and neither of them connect to VoWIFI while roaming. I am sure at least one of them allows this. VPN doesn't do anything either.

[kszaq]

I have the same issue with Orange PL: as soon as SIM card is in "roaming" state, Pixel does not register to VoWiFi. The only workaround for now is to use Flight Mode with WiFi enabled, then I can call without issues. More importantly, I have a local eSIM that provides data and "backup calling" refuses to work because of roaming. I'm still looking if there's a flag that prevents VoWiFi registration while roaming.

[kszaq]

I might have found an answer to this issue... There is a flag called carrier_default_wfc_ims_roaming_enabled_bool - additionally, when you look up the Android code, most carriers have carrier_supports_ss_over_ut_bool enabled (https://cs.android.com/search?q=carrier_default_wfc_ims_roaming_enabled_bool).

With these 2 flags in config override, it is working for me, both as "WiFi Calling" and "Backup calling":

mPersistentOverrideConfigs : 
        carrier_default_wfc_ims_enabled_bool = true
        carrier_default_wfc_ims_roaming_enabled_bool = true
        carrier_supports_ss_over_ut_bool = true
        carrier_volte_available_bool = true
        carrier_wfc_ims_available_bool = true

You can try an APK with this modifcation, remember to uninstall original version first because the signature won't match:
app-debug.zip
Source code patch:
diff.txt

How to use: reset carrier configuration to default in the app, then enable VoLTE (optional), VoWiFi but do not enable "Show VoWiFi Roaming Preference in Settings".

[xantrk]

This fixed it for me as well! Thanks for sharing this! Needed a reboot on top of everything but it did the trick!

Edit: It looks like without rebooting I'm not able to get wifi call connected again (with disabling and reenabling). But still very good!

[kszaq]

I don't have issues with WiFi call not working after a reboot, I made several calls before/after rebooting and it worked fine.

I've been checking a little bit more and it looks like carrier_supports_ss_over_ut_bool is not required, after all. The flag that does the trick is carrier_default_wfc_ims_roaming_enabled_bool:

mPersistentOverrideConfigs : 
        carrier_default_wfc_ims_enabled_bool = true
        carrier_default_wfc_ims_roaming_enabled_bool = true
        carrier_volte_available_bool = true
        carrier_wfc_ims_available_bool = true
        carrier_wfc_supports_wifi_only_bool = true
        hide_lte_plus_data_icon_bool = false

Here is the APK:
app-debug2.zip
And diff:
diff2.txt

I will PR these next week.