That's not H930 (the European model) but H931 (AT&T model). They are very different. Even if you COULD convert your phone back to H931 (which you can't) it's not going to help you as H931 won't have carrier configs for Indian carriers.Well it's the AT&T variant, which I got unlocked and then flashed to US99830b. So yeah its the H930. And thanks for the heads up! If I find it even a bit risky, I'll just say meh to Volte and make do with what I have.
Do you know anybody who has a H930DS?
In any case, study that thread I linked. Maybe H930DS owners shared information in there that you can use.