Database Users

HD Voice for Verizon on unlocked G6, model us997?

Going into settings, advanced calling, and the HD voice setting is greyed out. Does that mean the unlocked LG G6 does not work with HD voice on Verizon?

I would also like to know this but it looks like no one knows or cares to answer.

Try making a call then reboot.

Update: HD calling works on Verizon. But you have to go into settings on the Verizon website for your account to turn it on first. Second, go into settings on the G6 and the option will be available to turn on (no longer greyed out).

LG G6 US997 Oreo update and HD Voice
I received the LG US997 unlocked Oreo update last night. And now my HD calling magically works on straight talk with a straight talk Verizon sim. Also hotspot is still working as well.

Wifi Calling/VoLTE on H910 on T-Mobile

I have a H910 (ATT) edition of the V20 and I've tried to enable wifi calling. The SIM however, is T-Mobile. Enabling wifi-calling leads to an error and I'm guessing the reason is because I'm using a different network. Also, VoLTE doesn't work (I've done test calls and the 4g LTE icon turns into 4g during the call).
My question is:
Is there any way to enable wifi calling and/or VoLTE for T-Mobile on the H910 through the stock ATT firmware (I've done some digging around the field test menu @ *#546368#*910# but it's too out of my depth)
If not, is there any ROM that I can flash to the H910 to make it compatible with T-Mobile VoLTE services/wifi calling.
Thanks in advance.

saltyJeff said:
I have a H910 (ATT) edition of the V20 and I've tried to enable wifi calling. The SIM however, is T-Mobile. Enabling wifi-calling leads to an error and I'm guessing the reason is because I'm using a different network. Also, VoLTE doesn't work (I've done test calls and the 4g LTE icon turns into 4g during the call).
My question is:
Is there any way to enable wifi calling and/or VoLTE for T-Mobile on the H910 through the stock ATT firmware (I've done some digging around the field test menu @ *#546368#*910# but it's too out of my depth)
If not, is there any ROM that I can flash to the H910 to make it compatible with T-Mobile VoLTE services/wifi calling.
Thanks in advance.
Click to expand...
Click to collapse
Well, you're not alone in your quest, my friend....I went ahead and played around with the settings. All that I was able to do, was to "turn on" the Wifi Calling signal icon, but Wifi Calling never gets provisioned. I tried using a Google Voice number with the "use your number" option within Voice, and the receiving phone, displayed the Voice number. If you try clicking on the "edit e911 address" option, nothing happens.
There is a ROM that looks promising at the moment. I'm debating on flashing it now, or tomorrow. Here's the link: https://forum.xda-developers.com/v20/development/rom-natf-1-00-test-5-debloated-stock-t3509750.

You can try flashing system from the H918. The worse that is going to happen is your phone doesn't boot, and you have to flash an H910 system back. I have never tried the stock H918 on my H910, so I will be curious if the RIL works "out of the box" so to speak.
-- Brian

runningnak3d said:
You can try flashing system from the H918. The worse that is going to happen is your phone doesn't boot, and you have to flash an H910 system back. I have never tried the stock H918 on my H910, so I will be curious if the RIL works "out of the box" so to speak.
-- Brian
Click to expand...
Click to collapse
Interesting. Now you got me thinking about trying it. Lol...Maybe tomorrow.

RobertVanHagar said:
Interesting. Now you got me thinking about trying it. Lol...Maybe tomorrow.
Click to expand...
Click to collapse
have you tried it yet?

Hey, sorry about the late reply. I haven't tried it yet. Been tweaking my phone and catching up on sleep..

are you able to get wifi calling and Volet on T-Mobile ?
saltyJeff said:
I have a H910 (ATT) edition of the V20 and I've tried to enable wifi calling. The SIM however, is T-Mobile. Enabling wifi-calling leads to an error and I'm guessing the reason is because I'm using a different network. Also, VoLTE doesn't work (I've done test calls and the 4g LTE icon turns into 4g during the call).
My question is:
Is there any way to enable wifi calling and/or VoLTE for T-Mobile on the H910 through the stock ATT firmware (I've done some digging around the field test menu @ *#546368#*910# but it's too out of my depth)
If not, is there any ROM that I can flash to the H910 to make it compatible with T-Mobile VoLTE services/wifi calling.
Thanks in advance.
Click to expand...
Click to collapse
hi,
Did you find a way to make h910 get wifi calling/volte on T-mobile network ?
thanks

AT&T & Verizon VoLTE and VoWiFi calling/texting thread

Hi all. Posting this for users looking for answers on VoLTE and WoWifi on the 6T on AT&T & Verizon. If users with access to the OP6T could please test and report, that would be very helpful. Since the pixel 3 now supports both VoLTE & VoWiFi (on AT&T) there is perhaps some hope that OnePlus will also support it.
1: On AT&T, is there an option for Voice over LTE and Wifi calling and does it work?
2: On Verizon, I know Voice over LTE will work, but what about Wifi Calling?
Screen shots welcome I will have my hands on the device as soon as its available and will report since I have all the carriers, but thought maybe someone might get their hands on one early and could report. It might make a big difference on whether or now some users buy the device.! Thanks guys!

Yeah, whether or not I get the OP6T depends entirely on whether VoLTE and VoWiFi work on AT&T.
Eagerly waiting for updates!

hosss870 said:
Yeah, whether or not I get the OP6T depends entirely on whether VoLTE and VoWiFi work on AT&T.
Eagerly waiting for updates!
Click to expand...
Click to collapse
Same here!

AT&T & Verizon VoLTE and VoWiFi calling/texting thread
Same here. I’ve got a spot in SC where I got for holidays annually where, without Wi-Fi calling, my phone is a paperweight. I’ve always wanted to try a OnePlus but if there’s no Wi-Fi calling I’ll have to pass and stick with my XS Max.
I’ve already ordered but it’ll be a quick turnaround if that doesn’t work.
Sent from my iPhone using Tapatalk

This question came up in the AMA with the OP team in their community forums last week, and Pei himself said VoWifi isn't supported at the moment.

Just got my device today so update time..
1: VoLTE works on Verizon by default as soon as you pop in the SIM. All the Verizon LTE bands seem to work fine.. in this area, 2,4,13, & 66. no option in the menu for wiFi calling, even though it works fine in my pixel 3 where my verizon SIM just was.
2: Neither VoLTE or VoWiFI work on AT&T by default. No option for either in the settings at all. So no change there from OP5/5T/6 ETC. However, if you go do the dialer, dial *#800# and hit enter, select oneplus logkit, scroll down to function switch and select it, and check the box for VoLTE switch and Vowifi switch and then reboot, it puts the VOLTE setting and VoWiFI setting in for both the Verizon and AT&T SIM. and while you can enable VoWIFI on both Verizon and AT&T, it DOES NOT work on either. On AT&T however, as long as you have a VOLTE capable/recognized IMEI on your AT&T account for your line, VoLTE/HD voice work just fine.
So, while it is amazing to have, for the first time ever a DUAL SIM phone that supports both VZW & AT&T at the same time, it is a too bad that VoWiFI does not work on either, Especially now that the Pixel 3 Supports it on both carriers.

crowsnestitsupport said:
Just got my device today so update time..
1: VoLTE works on Verizon by default as soon as you pop in the SIM. All the Verizon LTE bands seem to work fine.. in this area, 2,4,13, & 66. no option in the menu for wiFi calling, even though it works fine in my pixel 3 where my verizon SIM just was.
2: Neither VoLTE or VoWiFI work on AT&T by default. No option for either in the settings at all. So no change there from OP5/5T/6 ETC. However, if you go do the dialer, dial *#800# and hit enter, select oneplus logkit, scroll down to function switch and select it, and check the box for VoLTE switch and Vowifi switch and then reboot, it puts the VOLTE setting and VoWiFI setting in for both the Verizon and AT&T SIM. and while you can enable VoWIFI on both Verizon and AT&T, it DOES NOT work on either. On AT&T however, as long as you have a VOLTE capable/recognized IMEI on your AT&T account for your line, VoLTE/HD voice work just fine.
So, while it is amazing to have, for the first time ever a DUAL SIM phone that supports both VZW & AT&T at the same time, it is a too bad that VoWiFI does not work on either, Especially now that the Pixel 3 Supports it on both carriers.
Click to expand...
Click to collapse
proof

crowsnestitsupport said:
Hi all. Posting this for users looking for answers on VoLTE and WoWifi on the 6T on AT&T & Verizon. If users with access to the OP6T could please test and report, that would be very helpful. Since the pixel 3 now supports both VoLTE & VoWiFi (on AT&T) there is perhaps some hope that OnePlus will also support it.
1: On AT&T, is there an option for Voice over LTE and Wifi calling and does it work?
2: On Verizon, I know Voice over LTE will work, but what about Wifi Calling?
Screen shots welcome I will have my hands on the device as soon as its available and will report since I have all the carriers, but thought maybe someone might get their hands on one early and could report. It might make a big difference on whether or now some users buy the device.! Thanks guys!
Click to expand...
Click to collapse
Has anyone used the dialer code *#*#4636#*#* & try to toggle VoLTE &/OR VoWI-FI ?

Thanks for the info. I'm looking to get the 6T to use on AT&T. I've never used an unlocked/non-AT&T branded phone on my line. Are there any other limitations that AT&T implements on non-AT&T branded devices? Do they throttle data speeds? Any issues with SMS/MMS working like some Verizon users are experiencing? Would I need to contact AT&T to have any special provisioning just to get it to work? I appreciate any insight on this.

sharksfan7 said:
Thanks for the info. I'm looking to get the 6T to use on AT&T. I've never used an unlocked/non-AT&T branded phone on my line. Are there any other limitations that AT&T implements on non-AT&T branded devices? Do they throttle data speeds? Any issues with SMS/MMS working like some Verizon users are experiencing? Would I need to contact AT&T to have any special provisioning just to get it to work? I appreciate any insight on this.
Click to expand...
Click to collapse
I'm not on AT&T so,I'm not gonna speculate.
Perhaps someone will chime-in soon for more definitive information.

My OnePlus 6t came in today. Took sim out of my Pixel 3 XL and popped it in. Everything is working except I can't SEND text messages. I can receive them and make calls, data is fine (actually amazing 44.5 mbps d/l, which is good for around here.)
I've tried chatting with Verizon, but after I told them what device, there was a long pause and then she asked if it was an iPhone
Here are my troubleshooting steps I've followed.
-deleted app cache and storage
-reset device
-factory reset device
-cleared cache partition in recovery
Any suggestions? I put the sim back in my Pixel and all the messages came through. I've tried both slots.
Mobile network state-Connected
Service state-In service
Mobile voice network type-4g
Mobile data network types-4g
EID-unknown (??)

There is another thread discussing why a lot of people using 6T on Verizon having problem receiving SMS and MMS. Something the phone being LTE only on Verizon. Maybe you are having the same problem? Worth reading that thread.

akmsr said:
There is another thread discussing why a lot of people using 6T on Verizon having problem receiving SMS and MMS. Something the phone being LTE only on Verizon. Maybe you are having the same problem? Worth reading that thread.
Click to expand...
Click to collapse
Yes. that would be best. I didn't need to do anything with mine, it just worked. However, I do have the latest version the the Verizon SIM card. Not sure if that matters. I was using a Pixel 3 before.

sharksfan7 said:
Thanks for the info. I'm looking to get the 6T to use on AT&T. I've never used an unlocked/non-AT&T branded phone on my line. Are there any other limitations that AT&T implements on non-AT&T branded devices? Do they throttle data speeds? Any issues with SMS/MMS working like some Verizon users are experiencing? Would I need to contact AT&T to have any special provisioning just to get it to work? I appreciate any insight on this.
Click to expand...
Click to collapse
I have used AT&T for years on unlocked devices. I have tested everything Data speeds are just fine. no issues there. the OP6T supports all the bands on AT&T so coverage should be just fine for you. The limits are as follows:
1: built in visual voicemail will not work, you will need to use the AT&T visual Voicemail app from the store.
2: Wifi calling/texting will not work
3: VoLTE/HD Voice will only work with the above mentioned trickery. Root is NOT needed. just the *#800# thing
the only provisioning you may need is the AT&T imei for VoLTE (Easiest to do online) after installing your AT&T SIM in the OP6T, if VoLTE doesn't work after following the instruction in this thread, log into your AT&T account and update your IMEI to one of your past AT&T phones that support VoLTE and update, reboot you OP6T and bingo, it will work. No other provisioning or limitations that I know of. And if VoLTE/HD Voice isn't important to you, you can ignore all this. Your existing AT&T SIM just needs installed in your OP6T and your good to go!

KOLIOSIS said:
Has anyone used the dialer code *#*#4636#*#* & try to toggle VoLTE &/OR VoWI-FI ?
Click to expand...
Click to collapse
The *#800# enables all those options. But it doesn't help anything on Verizon, and on AT&T it does work for VoLTE if a VOLTE enabled IMEI is on your AT&T account, but it doesn't work for wifi calling. I wish it was just illegal for the carriers to block services just because its a non branded phone

natypes said:
My OnePlus 6t came in today. Took sim out of my Pixel 3 XL and popped it in. Everything is working except I can't SEND text messages. I can receive them and make calls, data is fine (actually amazing 44.5 mbps d/l, which is good for around here.)
I've tried chatting with Verizon, but after I told them what device, there was a long pause and then she asked if it was an iPhone
Here are my troubleshooting steps I've followed.
-deleted app cache and storage
-reset device
-factory reset device
-cleared cache partition in recovery
Any suggestions? I put the sim back in my Pixel and all the messages came through. I've tried both slots.
Mobile network state-Connected
Service state-In service
Mobile voice network type-4g
Mobile data network types-4g
EID-unknown (??)
Click to expand...
Click to collapse
Here are various threads.. Not sure if there are answers. But again, it just worked for me.. Sorry I'm not more help.
https://forum.xda-developers.com/oneplus-6t/help/verizon-oneplus-6t-im-happy-one-t3863258
https://forum.xda-developers.com/oneplus-6t/help/feeling-6t-verizon-t3861188
https://forum.xda-developers.com/oneplus-6t/help/wifi-calling-incoming-phone-calls-text-t3863595
https://forum.xda-developers.com/oneplus-6t/help/verizon-to-to-sms-t3863352

crowsnestitsupport said:
Just got my device today so update time..
1: VoLTE works on Verizon by default as soon as you pop in the SIM. All the Verizon LTE bands seem to work fine.. in this area, 2,4,13, & 66. no option in the menu for wiFi calling, even though it works fine in my pixel 3 where my verizon SIM just was.
2: Neither VoLTE or VoWiFI work on AT&T by default. No option for either in the settings at all. So no change there from OP5/5T/6 ETC. However, if you go do the dialer, dial *#800# and hit enter, select oneplus logkit, scroll down to function switch and select it, and check the box for VoLTE switch and Vowifi switch and then reboot, it puts the VOLTE setting and VoWiFI setting in for both the Verizon and AT&T SIM. and while you can enable VoWIFI on both Verizon and AT&T, it DOES NOT work on either. On AT&T however, as long as you have a VOLTE capable/recognized IMEI on your AT&T account for your line, VoLTE/HD voice work just fine.
So, while it is amazing to have, for the first time ever a DUAL SIM phone that supports both VZW & AT&T at the same time, it is a too bad that VoWiFI does not work on either, Especially now that the Pixel 3 Supports it on both carriers.
Click to expand...
Click to collapse
So glad that I found this post. I am coming from an AT&T branded Galaxy S8 to my new OnePlus 6T. The above instructions worked like a charm for AT&T. I ran some tests. The OnePlus displays "HD" when I call my wife on her phone on AT&T and VoLTE shows in the status bar. When I toggle it back off I lose "HD" on the phone call screen. Also, LTE stays on during calls with VoLTE turned on and I ran a speedtest with it on and off and I definitely get 4G speed with it on and it downgrades to HSPA+ with VoLTE off and speed goes way down. Hopefully VoWIFI will be supported soon but that's not a deal breaker for me as I get great reception most of the time where I live, work and travel.

KOLIOSIS said:
Has anyone used the dialer code *#*#4636#*#* & try to toggle VoLTE &/OR VoWI-FI ?
Click to expand...
Click to collapse
I am on att had it all working on my unlocked NOTE 8. Now I can't even get volte cause it's all grayed out.

The service providers don't want you to buy unlocked phones. They make zero on them!! So that's why they block stuff. It's an antitrust lawsuit waiting to happen!! A$$h0!€$
Sent from my SM-N960U using Tapatalk

I've got AT&T as my primary and Verizon as #2. I just got off the phone with Verizon, told them I needed to add the CDMA Less feature to fix my texting. He checked a box on his end and I got a flood of texts in...what was even better, it was a work phone on a business account. I didn't even have to provide any real information to him and he was able to fix me up. He was aware of the issue though, he'd asked if it was a 6T from T-Mobile...so someone sent out a bulletin somewhere that he had read.
Anyway, I left Verizon to go to AT&T specifically for this plan of having one phone to cover 2 lines while one being fully functional (AT&T), so far it's been working well switching between SIMs for texting and making phone calls.
What were you specifically looking to find out?
Edit: found what you're looking for...however I'm not sure where those settings are even at.

VOLTE Wifi Calling with Unlocked S10+

Hey there, I've been doing a bit of research but it has been a long while since i have done any flashing of firmware etc. I received my s10+ device today. Model number is SM-G975UZKAXAA. I am a Verizon wireless customer. When I placed this device on my account I noticed I have no access to Voice over LTE, and I also do not have any access to Wifi Calling. My question is the following. I read somewhere a couple of weeks ago that if I wanted something like this I would need to flash the original VZW Firmware which would have all the lovely bloatware etc on the device. Is there any way I can do that? I have seen firmware that has been posted but I dont seem to see anything that specifically is the VZW apps etc which should (hopefully allow VOLTE and Wifi Calling and maybe even HD Calling, if thats a thing)
I would appreciate any info anyone can provide me on this, as the only solution I can see at the moment is to return the device and start over with a VZW specific device.
Cheers~

Likewise but with a T-Mobile firmware for me

Unlocked US version here with Verizon and wifi calling and volte working out of the box.
You may want to call Verizon to see if they need to provision it for your account.
Sent from my SM-G975U1 using Tapatalk

clubtech said:
Unlocked US version here with Verizon and wifi calling and volte working out of the box.
You may want to call Verizon to see if they need to provision it for your account.
Sent from my SM-G975U1 using Tapatalk
Click to expand...
Click to collapse
Same here!! Really happy about it too as my unlocked Note 9 did not work.
Sent from my SM-G975U1 using Tapatalk

clubtech said:
Unlocked US version here with Verizon and wifi calling and volte working out of the box.
You may want to call Verizon to see if they need to provision it for your account.
Click to expand...
Click to collapse
skinnytoo2 said:
Same here!! Really happy about it too as my unlocked Note 9 did not work.
Click to expand...
Click to collapse
Hey guys, just wanted to check in with you (or anyone else who has wifi calling on unlocked Verizon). It is 100% working? It's the only reason I got the carrier version. Should I cancel and order the unlocked?

AB_ said:
Hey guys, just wanted to check in with you (or anyone else who has wifi calling on unlocked Verizon). It is 100% working? It's the only reason I got the carrier version. Should I cancel and order the unlocked?
Click to expand...
Click to collapse
Yes, it works with my unlocked S10+ on Verizon. It surprised the heck out of me as I too have the unlocked Note9, but no wifi calling.

What about on AT&T? Can anyone say if they can at least get VOLTE? WiFi calling would be the icing on the cake. Thank you

lyall29 said:
What about on AT&T? Can anyone say if they can at least get VOLTE? WiFi calling would be the icing on the cake. Thank you
Click to expand...
Click to collapse
And T-Mobile?

dchurch85 said:
And T-Mobile?
Click to expand...
Click to collapse
Wifi calling worked on my unlocked S10 out of the box on T-Mobile. I'll try and check on VoLTE later but I get **** reception near work.

Can you explain how you enabled WiFi calling on unlocked version, on Verizon? I can't find a way to do it. What about HD Voice? My real problem is that data does not work while on a call, using my unlocked, on Verizon. Is there a way to get that working?

I have unlocked S10+ on VZW. I get LTE+ which is VoLTE, data works while on a call.
Sent from my SM-G975U1 using Tapatalk

Warwizard said:
Hey there, I've been doing a bit of research but it has been a long while since i have done any flashing of firmware etc. I received my s10+ device today. Model number is SM-G975UZKAXAA. I am a Verizon wireless customer. When I placed this device on my account I noticed I have no access to Voice over LTE, and I also do not have any access to Wifi Calling. My question is the following. I read somewhere a couple of weeks ago that if I wanted something like this I would need to flash the original VZW Firmware which would have all the lovely bloatware etc on the device. Is there any way I can do that? I have seen firmware that has been posted but I dont seem to see anything that specifically is the VZW apps etc which should (hopefully allow VOLTE and Wifi Calling and maybe even HD Calling, if thats a thing)
I would appreciate any info anyone can provide me on this, as the only solution I can see at the moment is to return the device and start over with a VZW specific device.
Cheers~
Click to expand...
Click to collapse
Unlocked S10e on T-Mobile. WiFi Calling, VoLTE and band 12 are working. There is no setting for VoLTE, but it works

Jeremyinsf said:
Can you explain how you enabled WiFi calling on unlocked version, on Verizon? I can't find a way to do it. What about HD Voice? My real problem is that data does not work while on a call, using my unlocked, on Verizon. Is there a way to get that working?
Click to expand...
Click to collapse
For WiFi calling on Unlocked:
Open Dialer
Click 3 dots
Settings
Hit the slider for Wi-Fi Calling to enable.

dchurch85 said:
And T-Mobile?
Click to expand...
Click to collapse
WiFi calling and volte works ?

skinnytoo2 said:
I have unlocked S10+ on VZW. I get LTE+ which is VoLTE, data works while on a call.
Sent from my SM-G975U1 using Tapatalk
Click to expand...
Click to collapse
I don't think that is right. LTE+ and VoLTE are different things. As well as data while on a call.
VoLTE means your call is being transmitted over LTE. I'm pretty sure you can use data while on a call WITHOUT VoLTE.
---------- Post added at 03:33 AM ---------- Previous post was at 03:30 AM ----------
Shuthefrontdoor said:
WiFi calling and volte works
Click to expand...
Click to collapse
How do you test if VoLTE is working? Do you get an Icon for it?
I tested WiFi calling by going into airplane mode, turning Wifi on, and making a call and it worked. But didn't get a special icon for it.

For those basing your decision to buy unlocked/international vs branded, be warned. I can only speak for Att, but I spent about 2 hours arguing with their level 2 tech department and here's what I have learned. If you have a sim that is provisioned on a branded phone and then put the sim into an unlocked/international phone, you will be able to use volte, wi-fi calling, etc., but only until the carrier pings your imei for a periodical check, once that happens, those features disappear. Also, on Android Pie, the Enhanced LTE Services tab under Mobile Data has been removed as it is turned on by default, also confirmed with ATT. The only way to manually check is to toggle wifi calling on and see if it works. Anyway, just trying to help as I have gone to a branded phone for the first time in 6 years because the reception and enhanced features are more important than rooting to me.

I was able to get wifi and volte working on my unlocked s10 by putting sim into verizon phone, letting network recognize it, enabling advanced calling and such on that device and then taking the sim out and putting it back in my new unlocked s10. The option for volte appears in settings-connections-mobile networks.

VoLTE works on tmobile, not that anyone should be surprised. That has been the case for the S8 thru N9. Now... I noticed that Samsung removed the VoLTE toggle from settings.

Ace42 said:
VoLTE works on tmobile, not that anyone should be surprised. That has been the case for the S8 thru N9. Now... I noticed that Samsung removed the VoLTE toggle from settings.
Click to expand...
Click to collapse
Correct, no VoLTE setting on my unlocked S10e, but it is on by default it seems

samappz said:
I was able to get wifi and volte working on my unlocked s10 by putting sim into verizon phone, letting network recognize it, enabling advanced calling and such on that device and then taking the sim out and putting it back in my new unlocked s10. The option for volte appears in settings-connections-mobile networks.
Click to expand...
Click to collapse
Using what I learned in this thread, I called Verizon and talked to Level2 support. They tried to get everything working and could not - but this was when I had the new SIM installed, provided by Samsung when I got my S10+.
So because others here spoke of their 'other' SIM, I suggested we try that - so I plugged in the SIM from my S8 and asked them to reprovision everything. They did... and....Now everything that didn't work ... WORKS.
So I have an Unlocked S10+ on Verizon that has (among other things):
- Wifi Calling
- Real Time Text
- VoLTE ("HD Voice") (Which means data now works while I'm on a phone call)
- Visual Voicemail
So it seems the Samsung SIM was part of the problem, and they are reporting this to Samsung. The tech support person told me others have reported similar issues and they will get with Samsung to figure out what the issue is.
Hopefully this helps some others as well!

? Using LG V20 H910 AT&T Model On T-Mobile After (2021) VoLTE Change

I posted this ? on reddit as well; however, this device is on its last legs so there's not much interest for it. I've gotten some good answers here and there on this website, but a dedicated thread to gather all the good info might be more helpful.
I still use my AT&T H910 as I don't really do much gaming on it. Calling, texting, and YouTube is what I mostly utilize it for. I just heard about the whole VoLTE requirement on specific devices after 2022 for AT&T, and 2021 for T-Mobile.
I spoke to AT&T, and they re-assured that the H910 was going to be one of the devices supported after 2022; however, I've been thinking about changing to T-Mobile (my family has a great plan with them, and I always switch back and forth between carriers based on who gives me the best deal) but I can't seem to get a straight answer from T-Mobile about whether my unlocked H910 will work with them after 2021; some didn't even know about the 2021 specifics of it.
I know AT&T will have to allow devices to be used on their network after 2022 even if they're VoLTE capable already. By the looks of it, T-Mobile won't go to that extreme; however, does anyone know exactly how VoLTE works? Specially in regards to using the AT&T H910 model on T-Mobile? Does my H910 has the required Bands to utilize VoLTE on T-Mobile? Or is it one of those things like "Wi-Fi Calling" where T-Mobile Wi-Fi calling only works with the LG V20 model from T-Mobile, and AT&T Wi-Fi calling only works with the LG V20 model from AT&T?

You need band 12 support which H910 has. Also a rom with IMS services working so no AOSP roms.
Volte works by using IMS processes in the rom to route phone calls over IP. No volte = no phone calls. But the device will still "work".
In theory the ATT software will work, unlock it and borrow someone else's sim. In theory a partial cross flash (just system, no modem/aboot/etc) could work if it doesn't.

nxb said:
You need band 12 support which H910 has. Also a rom with IMS services working so no AOSP roms.
In theory the ATT software will work, unlock it and borrow someone else's sim.
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Click to collapse
I was recommended to use an app called Network Mode Universal on reddit for VoLTE testing purposes, and after inserting a T-Mobile SIM card that I borrowed on my unlocked H910 and using the application, the Voice Network Type tab says "LTE". Which is supposed to be a sign that VoLTE might be working on the H910 using a T-Mobile SIM, but that's all I know; just what people tell me.
Update:
The person who recommended that Network Mode Universal app forgot to mention that you have to actually make a call to know whether the phone supports VoLTE with the SIM card in use. When actually making a call, the Voice Network Type tab changes from "LTE" to "UMTS". Which means the H910 is not VoLTE capable on T-Mobile.
Sent from my LG-H910 using Tapatalk

Could also be how his sim is set up. Volte has to be enabled there and in the phone. My suggestion would be to force LTE only on the device as well. Does it use VOLTE on his phone?
Also look at IMS registration in the phone and see if it's registered.

nxb said:
Could also be how his sim is set up. Volte has to be enabled there and in the phone. My suggestion would be to force LTE only on the device as well. Does it use VOLTE on his phone?
Also look at IMS registration in the phone and see if it's registered.
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The person I borrowed the T-Mobile SIM from uses an iPhone on iOS 13. According to him, the option for turning on/off VoLTE from the settings is gone. He used to be able to turn it on and off at will; not anymore after iOS 13. It should be enabled by default on an iPhone though, I don't see why it would be off. It's almost a necessity on an iPhone I would think.
The LG V20 seems to be more limited in that sense, as on my previous Samsung phone I could enable 2G, 4G, LTE, etc, individually to force only one. I don't see any of those settings on my H910. I don't see any IMS info either.
Either way, I doubt T-Mobile would bother servicing my AT&T branded H910 phone in case IMS needed to be registered; in the case that it wasn't already. I've had really bad luck in the past dealing with T-Mobile on phones that are not T-Mobile branded.
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IMS has a phone component and a sim component.
you can check status in the service menu of IMS on the H910. Hope it works on my Tmo phone, getting my sim upgraded

nxb said:
IMS has a phone component and a sim component.
Hope it works on my Tmo phone, getting my sim upgraded
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It should work if it's a T-Mobile phone. The H918 is 40% more expensive, so it would be great if the H910 worked with T-Mobile; however, it's not looking good.
Sent from my LG-H910 using Tapatalk

Eh, kinda. I'm having trouble too. My IMS services aren't connecting. Going to try a few different roms. I'm through an MVNO so still trying to get them to understand ISIM vs USIM.
see: https://www.quora.com/Are-4G-SIM-cards-of-two-types-VoLTE-and-LTE?share=1
https://www.slideshare.net/ikwe22/understanding-telecom-sim-and-usim-isim-for-lte

nxb said:
Eh, kinda. I'm having trouble too. My IMS services aren't connecting. Going to try a few different roms. I'm through an MVNO so still trying to get them to understand ISIM vs USIM.
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Gotcha, I hope it works. I was mentioning to @C D which has helped me understand a lot about VoLTE, that I'm starting to give in to the system of using whatever carrier my phone supports, as long as I can keep using my H910. The removable battery & IR blaster era has come to an end, and I don't think I need another phone right now other than the V20. I might even consider going back to the AT&T MVNO I was using before.
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Latest result: oreo works but not nougat.
IMS never registers. Maybe I can fix it. At least now OK sim-wise. Unfortunately doing the sim swap broke tethering.

Hi guys, I am sorry for reviving the old thread.
I too owned H990DS Sea version on latest nougat. It has volte option but just couldn't switch on.
Please take a look at this thread on LG G8
https://forum.xda-developers.com/t/...ther-qualcomm-powered-lg-devices-too.4343655/
I tried on my H990DS using the above thread's method and it didn't work. I was informed that the mbn files are for LG G8. We need mbn files that are specific for LG V20. I have searched up and down and I couldn't find any.
So I hope that I have provided some insights and I hope any member/master/guru out there can help where to find the mbn file (collection of all international carriers mbn) and make volte works for H990DS.