Volte/Vowifi for Austrian Provider XOXO

[frankthecrank]

Thank you so much for your affort in creating that patch. I am curious, if there is a chance you could implement a way that the provider named "XOXO" is supported. Me and other users are not able the to get VoWifi working. (I tried to find a solution in a domestic lteforum.at)

The thing is Xoxo is a subsidiary company of one of the big providers in Austria, "A1".
Vowifi and Volte are fully working with pixel phones on A1. But not on Xoxo.

Even the settings are all available by default in the options, I wouldn't have to implement that with the patch.
Another subsidiary company called "bob" uses also the same network, and here Vowifi/Volte is working without the patch.

I already called the hotline of XOXO, they said it's a thing Google has to implement, and they have a bunch of complaints from users.

And here is where it gets weird. I bought a physical sim from Xoxo (good, inexpensive deal atm) and put it in my Pixel 9 Pro, Vowifi worked out of the box (just had to turn on the toggle in settings), but after a reboot it won't work anymore. Another user found out, that if he puts in a "magenta" (other provider) sim, and changes that one back to XOXO, vowifi and volte are working till he reboots the phone. Is there some kind of whitelist in the background??

So @kyujin-cho do you see any chance to get that thing working? Of course I am willing to support you with logs/dumps etc. if possible (I think I should be able to do so, with a little instruction).
I have access to XOXO (sim) and bob (esim).

Hoping for wonders here ;)

Best regards