yashsingh1/xdaforums huggingface dataset:
[Xiaomi Mi 9 Guides, News, & Discussion] gui.aguiar:
Already did it

---------- Post added at 09:19 PM ---------- Previous post was at 09:18 PM ----------

Thanks! How i'm able to turn on It off in settings, but its not working yet. And i Stilo cant turn It on in MCC code (*#*#4636#*#*)
[Xiaomi Mi 9 Guides, News, & Discussion] gtgtgt36:
I have a Mi9 on T-Mobile USA. Volte indicator is on and shows up next to signal meter. I can make outgoing calls just fine but I can't hear anything with incoming calls from non-VolTE lines (such as businesses or conference calls). Any ideas?
[Xiaomi Mi 9 Guides, News, & Discussion] Ducter:
I can offer no solution but since I got this phone about a week ago I've noticed I get calls that I can't hear a thing. I hadn't connected the dots yet that it might be volte. I don't use it as my main phone until I can root it and get rid of the privacy concerns so speaking from limited usage but thanks for the post, I'll have to try and figure it out as well.
[Xiaomi Mi 9 Guides, News, & Discussion] gtgtgt36:
Yeah it took me a while and some googling but after I read some random Indian Times article (of all places) that mentioned VoLTE issues, I started observing which calls had issues. Calls from my other T-Mobile lines or my mom's AT&T lines come in fine. However, I get dead air on calls from businesses or the Skype conference call-back number that my company uses (to bridge my phone to the conference)...

The call recording function is sort of a big deal for me which is why I really want to get calls working on this...As of now, turned VoLTE off and am falling back to UMTS for calls.
[Xiaomi Mi 9 Guides, News, & Discussion] Ulver:
I'm having similar issues too. I'm on T-Mobile US with voLTE activated via the dialer code. Have you narrowed it down to voLTE being the cause and turning it off fixes it? This is disappointing for their flagship which should function as a phone. Which ROM are you using? I'm on 10.2.9.0 global, I'm thinking about trying the weekly beta to see how that goes.
[Xiaomi Mi 9 Guides, News, & Discussion] gtgtgt36:
I haven't concluded 100% but I don't have the skills or time to do any more investigation on this. I'm seriously hoping for a fix since I love the phone otherwise. Turning off VolTE seems to fix my issue as it just falls back to old 3G network. I'm on the latest 10.2.24.0...please share if beta roms work!
[Xiaomi Mi 9 Guides, News, & Discussion] Ulver:
I did a test where I had a friend call me from his work/land line and I couldn't hear him with voLTE enabled. I turned off voLTE and tried it again, it worked just fine. So looks like I'll be keeping it off and testing again with the next update. I can't blame the phone too much as I wouldn't get voLTE out of the box.
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
I had the same problem on 10.2.24.0. I switched to the weekly ROM and so far I haven't had a call where I couldn't hear the caller. I have both Volte and Wi-Fi Calling enabled on MintSim which uses T-Mobile network.

I had to stop using the Mate 20P because some calls were going straight to voicemail without ringing. Apparently it was because T-Mobile requires phones that support band 12 to also support Volte.
[Xiaomi Mi 9 Guides, News, & Discussion] lightcao:
Same issue on my side. It is kinda annoying but what worked for me was staying on the call for another 10 secs for it to connect properly.
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
I was able to get two calls where I couldn't hear the caller by toggling the hold button on the call screen on and off.

Since the problem seems to have completely gone away once I switched to the weekly ROM it's possibly a problem with that specific build which I don't think was a regular stable update but a 'beta stable' that was only rolled out to some devices. Multiple users on XDA complained that the same build broke WiFi calling on their phones.
[Xiaomi Mi 9 Guides, News, & Discussion] gtgtgt36:
Could I ask you how you installed the weekly on the global version?

Thanks
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
I used a program called Xiaomi Tool V2 by Francesco Tescari that I found linked in another thread. My bootloader is still locked and the local update method kept giving me a can't verify package error but I was able to install the weekly with that program and have received two OTA updates since I switched. I have had no call issues on the weekly.
[Xiaomi Mi 9 Guides, News, & Discussion] lightcao:
I think I found a fix for good. Create a new APN and call it whatever you want. Here are the settings I used for T-Mobile. The most important thing I think is adding ims to the APN type.

APN: fast.t-mobile.com

MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc

MMC : 310

MNC: 260

APN type: default,supl,mms,ims,cbs

APN protocol: IPv4/IPv6

APN roaming protocol: IPv4/IPv6

With these settings, no more issues with VoLTE calls or WiFi Calls. Sound has gone through for me for every call I've gotten since and WiFi calling stays on forever instead of more than 5 mins at a time. Missed calls are no longer a concern. I hope this helps someone.
[Xiaomi Mi 9 Guides, News, & Discussion] tboguizmo:
ADD

# Debug Options

persist.dbg.ims_volte_enable=1

persist.dbg.volte_avail_ovr=1

persist.dbg.vt_avail_ovr=1

persist.dbg.wfc_avail_ovr=1

# Radio Options

persist.radio.rat_on=combine

persist.radio.data_ltd_sys_ind=1

persist.radio.data_con_rprt=1

persist.radio.calls.on.ims=1

with BuildProp Editor.apk and reboot.

Enjoy
[Xiaomi Mi 9 Guides, News, & Discussion] L0r3nz:
Works for me impressive good!

Thank you very much! :o :highfive:
[Xiaomi Mi 9 Guides, News, & Discussion] gtgtgt36:
Sadly this isn't working for me... Incoming calls where the originator is a landline still come in where I am unable to hear them.
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
The shortcut maker app in the Play Store can be used to access the greyed out network preference for WiFi Calling. While it looks in the greyed out setting that Wi-Fi Preferred is selected in reality Data Preferred is what is selected. This can be changed using shortcut maker and the change does stick after you do it.
[Xiaomi Mi 9 Guides, News, & Discussion] danon.brown:
What are you using to make the arrows?
[Xiaomi Mi 9 Guides, News, & Discussion] age-pi:
FastStone Capture
[Xiaomi Mi 9 Guides, News, & Discussion] eddiev1111:
Hi, i enable the volte and the wifi calling options but when i put in airplain mode and enable wifi only, try to call and its says radio disabled and not working. What else can i do?. Thanxs in advance.
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
You don't have VoWIFI, pushing the button in settings will do nothing.

Call your operator and ask for the option.

Proof :
[Xiaomi Mi 9 Guides, News, & Discussion] eddiev1111:
Hi, i call my operator and the enable the wifi call option. So, now i should see the wireless phone icon?
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
Yes
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
I had to play with it initially to get it to work. I used shortcut maker from the Play Store to change the setting for WiFi Calling to Wi-Fi Preferred. The setting was grayed out in my call settings and even though it showed Wi-Fi Preferred in shortcut maker it showed either data preferred or data only (I don't remember which).

I then toggled WiFi Calling off and on in my device settings and verified in shortcut maker that Wi-Fi Preferred was still selected.

After that Wi-Fi Calling was working for me and I could make calls in Airplane Mode.

It has continued to work after 2 OTAs so far
[Xiaomi Mi 9 Guides, News, & Discussion] tonarii:
I just updated to 10.2.26.0 EEA and thoses options are still not working anymore. Everything was ok when i was in 10.2.17, but since the last 3 updates it's not working anymore.
[Xiaomi Mi 9 Guides, News, & Discussion] alese13:
I'm on 10.2.26 and it's working for me!
[Xiaomi Mi 9 Guides, News, & Discussion] gerhard_wa:
I too just got this new EEA update and the VoLTE and VoWIFI still works here and the options are present.
[Xiaomi Mi 9 Guides, News, & Discussion] tonarii:
Thanks guys, i think this is a problem with my phone operator. And it's the only one who have this problem here in France, everything is fine with the other operators.
[Xiaomi Mi 9 Guides, News, & Discussion] NYG2009:
Has anyone tried this with AT&T?
[Xiaomi Mi 9 Guides, News, & Discussion] HTCDevil:
Activated on Optima (Vodafone) in Italy.
[Xiaomi Mi 9 Guides, News, & Discussion] denzel09:
VoLTE works really for you with Vodafone? When you make a call the phone stays in 4g?
[Xiaomi Mi 9 Guides, News, & Discussion] HTCDevil:
I am talking about VoWIFI, not about Volte, it is not my principal sim, on Tim i have volte and it works. Vodafone requires branded phone for having it work.
[Xiaomi Mi 9 Guides, News, & Discussion] malbert16442:
Hello everyone recently got this device and have the same issue where business calls coming in on volte connection has no sound from caller. Is there a update for this issue or the census is to use weekly builds. Using TMobile USA.
[Xiaomi Mi 9 Guides, News, & Discussion] cruel91:
Is anyone having a drop of wifi calling? I have to turn airplane mode on and off again to get it back. I am using T-Mobile US
[Xiaomi Mi 9 Guides, News, & Discussion] lightcao:
Try the Updated section in my first post. It's been working for me ever since I applied those settings. No more weird call behavior or dropped WiFi Calling. It is rock solid. I am on ROS but I'm pretty sure as long as it is MIUI based, you should be fine.
[Xiaomi Mi 9 Guides, News, & Discussion] malbert16442:
Yah I'm using those settings that appears not to be the issue. Volte and wfc works. Only when I receive incoming business calls there is no audio over Volte. These are numbers from a company or institution. Falling back to 3g resolves issue. I'm try some custom ROMs this week and see if I could replicate the issue to come down to the root of the problem or find a temp fix.
[Xiaomi Mi 9 Guides, News, & Discussion] lightcao:
Ahh I see. My next guess if we were to go down the line would be your sim card. Try swapping to the other slot, apply the settings, and reboot. All of these things aren't an exact science sadly so it is hard to tell what it could be. In the end, it could just be the Mi 9 or T-Mobile. Best of luck!
[Xiaomi Mi 9 Guides, News, & Discussion] cruel91:
I have the same setup. Wifi calling still drops in 24hrs. May I know which band you mostly use? You can use LTE Discovery app to know. I am currently on EEA, but will flash ROS when the bootloader timing is done. Thanks for the help.
[Xiaomi Mi 9 Guides, News, & Discussion] malbert16442:
Found or confirmed temp fix putting call on hold then switching off resolves issue
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
The last EEA build I was on had an issue where I couldn't hear the voice on incoming Volte calls. The issue completely went away when I switched to the Global Developer ROM. I'm currently on ROS and the issue hasn't returned. Like you I discovered that tapping the call hold button twice allowed me to hear the caller on the other end.
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
Also, the codes only work for 1 sim slot, and if you happen to one day have two sim cards, it's "game over" since the VoLTE activated slot will change to the sim card it was first activated for.

- Provider 1, Sim1 slot 1, Code entered, VoLTE for SIM 1 and SLOT 1

> Switching to a new provider, having the two SIM at the same time to avoid being without service

- Provider 1, Sim1 slot 1, Provider 2, Sim2 slot 2, VoLTE for SIM 1 and SLOT 1 only

> Entering and removing the code : VoLTE for SIM 1 and SLOT 1 only

> Provider 1 stops service, Sim1 thrown away

- Provider 2, Sim2 Slot 1, VoLTE for SIM1 and SLOT 2 > Game over

- Provider 2, Sim2 Slot 2, VoLTE for SIM1 and SLOT 1 > Game over

I did edit this post, since that problem is what led me to check for the build.prop solution.
[Xiaomi Mi 9 Guides, News, & Discussion] jhs39:
Are you on the EEA ROM? That was an issue reported by users last month on the same "stable beta" build that first caused the problem with not being able to hear incoming Volte calls.

The latest EEA OTA is apparently bricking some MI 9's as well.

Xiaomi is having problems with bugs in MIUI builds that are supposed to be stable but the EEA ROM for the MI 9 seems to be especially snake bitten.

If you are on the EEA ROM I would seriously consider switching to the Global instead which doesn't seem to be experiencing issues as serious as those on EEA.

If you can't switch via local update method and your bootloader is locked you can use the MIUI V2 tool that's available in a separate thread. It worked well for me when I switched from EEA to Global Stable to Global Beta while my bootloader was still locked.

Switching to Global Beta no longer makes sense since it is being discontinued at the end of July but it was nice while it lasted.
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
Nope, that's just Xiaomi doing an absolute garbage on that phone.

There is a line, in the build.prop, REMOVING VOLTE in EUROPE on PURPOSE.

WTF ?!!!

You have to be rooted

MAKE A BACKUP

Remove the # on that build.prop on the 4 persists

Add the other two persist if they aren't here by default

Save and reboot

On a side note, I will consider going to the global rom, but there might be some specific vendor shiz in the EEA Rom i'm currently investigating. I'm also trying to get the Google DIaler Visual VoiceMail to be set up, and it's a nightmare to get carrier info (vvm_type_OMTP parameters for example)

- For those being rooted and having a problem on EEA roms with the above activated, try downloading Activity Manager 3.3.0 (not on the play store for obvious reasons)

- Look for Modem Config

- Check if your country is in here, and your operator if you're lucky

> Path is Vendor/firmware_mnt/image/modem_pr/mcfg/configs/mcfg_sw/generic/eu for europe, I'm unsure about which folder is the generic/generic one (for MVNO for example, my guess is on "DT" but unsure)
[Xiaomi Mi 9 Guides, News, & Discussion] cruel91:
I am on latest Xiaomi.eu. I already have Volte and Vowifi enabled by dial code. They are working flawless. Should I still do the build pro method?

I enabled the modem config of my region and operator (tmobile usa). What does it do?
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
The build.prop trick is only here for dual-sim errors, when the codes only unlock one slot.

I'm unsure about the modem configuration, but it might be relative to carrier-specific settings, like "LTE time-before-disconnection-when-no-data-exchanged", IMS prototocals and that kind of stuff that can't be found elsewhere. I really have almost no idea, and I believe that the app carrier services is taking care of the "IMS" side of things, where the modem is all about 3G and 4G behavior.
[Xiaomi Mi 9 Guides, News, & Discussion] Minux31:
Thanks a lot for the tip, on xiaomi.eu Volte switch was disabled before build.prop modification (it was shown "disable by you operator" even if before it worked on global stable with codes), and after, volte works perfectly, many thanks ! :good:
[Xiaomi Mi 9 Guides, News, & Discussion] vitonline:
for me VoLTE is working now on Zain KSA but WIFI calling still not working did anyone manage to get it working?
[Xiaomi Mi 9 Guides, News, & Discussion] redbike:
+1
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
Wifi calling is another problem.

I had it working when I had fiber+4G on the same operator.

I believe that wifi calling might be blocked if the wifi you are on is not by the same operator.
[Xiaomi Mi 9 Guides, News, & Discussion] toscha42:
I've made different experience. I had no problems to use WiFi calling when I was traveling abroad recently. WiFi in the hotel definitely was from a different provider then my roaming partner. Device is running on Global Dev 9.6.27.

Cheers

Toscha
[Xiaomi Mi 9 Guides, News, & Discussion] vitonline:
When I put my SIM in IPhone WiFi Calling is working only with Mi 9 its not
[Xiaomi Mi 9 Guides, News, & Discussion] jimmygoska:
**EDIT**

Ignore this. Didn't realize that "VoLTE carrier check disabled" is what I wanted to see.... IBM

****

I was on the EEA when my global Mi 9 arrived yesterday. I used the Mi V2 tool to get onto the latest global stable ROM. I have two SIM cards in my device: a US T-Mobile (slot 1) and a UK 3 (slot 2).

With both ROMs I only get the VoLTE option for my UK sim card.

I have tried the VoLTE code in the OP but that doesn't change anything for the T-Mobile SIM card. When dialing *#*#4636#*#* I get "VolTE Provisioned OFF" with the switch greyed out.

I tried the APN settings from the T-Mobile page and the ones in the OP (almost the same except the two extra codes) but still no luck.

Any suggestions would be greatly appreciated.

Cheers!
[Xiaomi Mi 9 Guides, News, & Discussion] samuelmullerforrati:
Hi! I tried to use VoLTE on Brazil with TIM operator, and I didn't have success. Tried to disable VoLTE carrier check (*#*#4636#*#*) with and activate manually on the Calling settings, but it doesn't work. Did someone have sucess using VoLTE or WiFi Calling in Brazil? I'm a bit disappointed. Even WiFi Calling with Claro Brazil operator I didn't have success.
[Xiaomi Mi 9 Guides, News, & Discussion] dolence:
I have the same problem with same carrier - TIM Brasil.
[Xiaomi Mi 9 Guides, News, & Discussion] butlerdp1:
Thanks! Disabling the checking for VOLTE and VOWIFI worked!

Thank you for posting this. After I disabled the checking for VOLTE and VOWIFI, the options to turn them on appeared in Settings\Sim cards & mobile networks\SIM card settings. I turned them both on, and all is working now! Also, I echo others that say to check with your carrier to see if VOLTE and VOWIFI are enabled on their end. I did have to do that with the VOWIFI via my carrier (Simple Mobile (USA) (Uses T-Mobile's network)).

God bless,

Daren

Xiaomi Mi9 running MIUI Global 10.2.13
[Xiaomi Mi 9 Guides, News, & Discussion] occams-razor:
Has anybody solved the problem with VoLTE needing to toggle "hold" button in order to unmute the caller when it's from a VoIP or landline? I am on the latest (as of today aug-12,2019) stock global rom and the problem is still there. I tried adding a new APN as somebody suggested, but that doesn't fix this.

Also, as a work around is it possible to automatically toggle the hold button whenever a call is received. This is probably something more suited for a custom ROM instead of the stock ROM. Any ideas?
[Xiaomi Mi 9 Guides, News, & Discussion] T@z90:
My phone has volte enabled, but it doesn't connect to ims so it doesn't work (Vodafone Italy). Is there any way to make it work?
[Xiaomi Mi 9 Guides, News, & Discussion] robiom:
I've got a Mi9 with global ROM 10.2.13.0 and it has both VoLTE and the option to "Make calss using Wi-Fi" but that doesn't work. When I try to make a call it says no network available, connect to Wi-Fi to make a call but I am connected to Wi-Fi.

The Network preferences is greyed out so I can't change it from "Prefer mobile networks" to Prefer Wi-Fi".

Any suggestions would be really helpful.

Thanks

Rob
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
Call your provider and ask if it works on an iPhone. You might have to have Wifi & Mobile on the same provider.

- On Mi 9, Mobile + Fiber, same provider : VOLTE + Wifi call work

- On Mi 9, same fiber, new mobile provider : VOLTE only
[Xiaomi Mi 9 Guides, News, & Discussion] gerhard_wa:
Did you check with your operator if they have VoWiFi enabled for your mobile subscripion?
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
I'm updating my last post with the "definitive" fix for Wifi & VoLTE, including problems with IMS registration & RCS.

- For those on mi.com, don't hesitate to go to this post

- I'm ranting a bit on mi.com, but the way they build roms is an absolute nightmare - we know where the money was saved now....

FIX FOR VOLTE & VOWIFI, RCS on MIUI STOCK ROM

- Root needed

- ActivityManager 3.3.0 strongly recommended (com.sdex.activityrunner)

- Tested on STOCK EEA 10.2.30

- Please CANCEL any "dialer code" you might have input before, as it only works on one card slot ( VoLTE

*#*#86583#*#*

VoWIFI

*#*#869434#*#*

)

> It should say "Carrier check enabled"

I. Edit the SYSTEM/BUILD.PROP file

Remove the Xiaomi blocking lines in the build.prp & add/modify :

persist.dbg.ims_volte_enable=1

persist.dbg.volte_avail_ovr=1

persist.dbg.vt_avail_ovr=1

persist.dbg.wfc_avail_ovr=1

persist.radio.VT_ENABLE=1

persist.radio.rat_on=combine

persist.radio.data_ltd_sys_ind=1

persist.radio.data_con_rprt=1

persist.radio.calls.on.ims=1

persist.radio.volte.dan_support=true

persist.data.iwlan=1

persist.data.iwlan.ipsec.ap=1

persist.sys.cust.lte_config=true

persist.rcs.supported=1

>> Check for duplicates !

2. Reset and empty the app: "Google Carrier Services" (com.google.android.ims.apk)

3. Reboot

4. You should now have "IMS registered" when typing *#*4636#*#*

Additionnal fixes if needed====================================

Additionnal fixing can be made using the app "Activity Manager" listed at the beginning

> Launch "Modem Config" (com.xiaomi.mbnloader), find your carrier, enable, reboot

> Launch "com.qualcom.qti.ims.ImsSettings", input your number using the international version (+01999999999 for example)

More Additionnal checking if it still doesn't work

Check apns-conf.xml for your carrier IMS config, try IPV4V6 where necessary

NOTE : VoLTE has to be enabled by your carrier on your phone plan. Sometimes they will tell you "Your phone isn't listed as compatible - Of course because Xiaomi blocked it - but I can activate VoLTE anyway - Say yes"

To continue, the /system/etc/APNS-conf.xml is absolutely outdated, most of the info here seems to have been taken on a bad google check.

- I suggest everyone check this file and their carrier, add IPV4V6 support, etc
[Xiaomi Mi 9 Guides, News, & Discussion] Lagartixo:
Man you're the best!! I did it on my Mi 9 EEA 10.2.28.0 and VoLTE is working perfectly. Google carrier was not installed. I had to configure the modem to start VoLTE. I also added the IMS configuration in APNS-conf.xml. Many many thanks.
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
You're welcome, glad I could fix that horrible, horrible rom.

Keep in mind : you're gonna have to update build.prop AND the APNS-conf.xml every time you update the ROM.

I keep mine into the TWRP folder so that I don't forget.

I still don't know what the Android 10 Rom is gonna look like, I'm trying to get my hand on the K20Pro rom and decompress the system img to see if the mess is still the same.

Edit : just studied the K20Pro Indian ROM, there is hope, since it looks a LOT like the PIXEL 3XL Android 10 ROM, and the build.prop is way cleaner.

Let's pray....
[Xiaomi Mi 9 Guides, News, & Discussion] seemebreakthis:
Works in Hong Kong with Smartone. For some reason VoLTE is already enabled, so I only had to use this trick to enable Wifi calling also. Works perfectly.
[Xiaomi Mi 9 Guides, News, & Discussion] zaver:
What if my carrier is not listed in modem config?
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
You need to use a generic one suited for your continent, I think. I haven't studied MBN files and config unfortunately.
[Xiaomi Mi 9 Guides, News, & Discussion] Lagartixo:
Thanks for the suggestions. I will install EEA 10.2.30 and follow its recommendations. Let's pray Android 10 comes with clean bulid.prop and VoLTE working properly.

Enviado de meu MI 9 usando o Tapatalk

---------- Post added at 03:09 PM ---------- Previous post was at 03:04 PM ----------

I'm in Brazil and just changing the region of the modem VoLTE already works, but if you lose the signal it does not come back alone I have to enable and disable airplane mode. Editing build.prop prevents this from happening.

Enviado de meu MI 9 usando o Tapatalk
[Xiaomi Mi 9 Guides, News, & Discussion] RedWave31:
This fix is supposedly for EEA and GLOBAL version. You DO NOT have to change from Global to EEA to use it. The two roms are basically the same and have the same build.prop and the same problems.