3G/4G & VoLTE Questions

[RockStar2005]

Hello all, 

Some questions (Note: I have T-Mobile):

1) When the phone is on a call, instead of going to 4G (since no VoLTE, which I'm not happy about and we'll discuss in a second lol), it goes to 3G. Why is this happening?? I know it's the int'l version and all, but is there a way to alter it is so that it STAYS in 4G?? Any "flashware" that doesn't require unlocking the bootloader or rooting?? My parents have the Xperia Z1s which doesn't have VoLTE but was bought through T-Mobile, and it stays in 4G during calls, so ? lol

2) Is there any flashware to put VoLTE on this phone? I know some foreign versions of the XP have VoLTE, but apparently the int'l version does not. At least with VoLTE I'd have LTE during the call.

Thanks to anyone who thinks they can help!

[Uliwooly]

@RockStar2005

1 That's how your carrier handle data and calls

2 No, it won't work

[RockStar2005]

uli, 

But again, it's not. My parents are ALSO on T-Mobile (though they're phones are locked with T-Mobile and from T-Mobile, but why should that matter??), and they too do NOT have VoLTE on their phones. But their phones stay in 4G during calls. Mine switches back & forth from 3G to H+ (aka HSPA+). What gives??

[Uliwooly]

@RockStar2005

Keep in mind that T-mobile advertised H+ as 4G, which H+ it is NOT 4G LTE, it is faster than 3G but not LTE; so that could be the issue here, that your parent's network branded phones display 4G even if it's H+. 

[RockStar2005]

Keep in mind that T-mobile advertised H+ as 4G, which H+ it is NOT 4G LTE, it is faster than 3G but not LTE; so that could be the issue here, that your parent's network branded phones display 4G even if it's H+. 

Interesting. So is H+ actually 3.5G or 4G?? lol SO confusing. 

[Uliwooly · Accepted solution]

@RockStar2005

H+ it's 3.5G, but AT&T and T-mobile mislead people saying that H+ it's 4G, there seems to be a loophole and they took advantage of it. 

[RockStar2005]

Ok. Weird. lol But thanks! So my phone is switching b/t 3G and 3.5G/H+ then. Great! lol 

[Uliwooly]

@RockStar2005

from 3G to H+ to LTE 

[RockStar2005]

uli, 

No.......DURING a call, it switches back & forth between 3G & H+/3.5G....... it NEVER shows LTE until I'm OFF the call, and not 'til about 10 seconds after that occurs. 

[Uliwooly]

@RockStar2005

That's a bummer, you should contact Tmobile and ask them how they handle their calls