Question VoLTE not working since OneUI 4.0 Beta installation

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Dec 2, 2021
Hey bro make sure it's the latest firmware, the 120hz bug seems to have been fixed in the new update. So get the BUKF update
You are talking about this rom
Screenshot_20211204-172433_UC Browser.jpg


Dec 2, 2021
Today 7.12.2021 got new update BUKF fix 120 hz bug but but but... Volte and Wifi calling bugs still exists


New member
Jun 11, 2011
i suggest all those who are still on oneui 4 - pls submit an error report on the samsung members app with all the details - esp mentioning that its an unlocked phone bought in the US and not working when travelling to other countries like India.

To submit report - open Samsung Members app->Get Help (lower right)->Error report

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    Hello All,
    I posted this in Samsung Community, but unfortunately none was able to help. I am hoping XDA members could help fix this issue.

    I am facing a strange problem with my S21 Ultra Unlocked which was directly bought from Samsung. I had enrolled into OneUI 4.0 beta when I was in the US. I was using Sprint connection then.

    I had to travel back to my home country (India) and I am using an Airtel sim card (LTE) here. Now, the strange problem is that LTE (data) works here fine. But, VoLTE is not working. The network changes to 2G for phone calls. I am assuming that the auto-switching bands which was introduced in OneUI 4.0 is causing the problem.

    Using Smart Switch PC, I rolled back to One UI 3.1. VoLTE and WiFi calling started to work again. But, soon after I got update notification for One UI 4 beta. To confirm that it is indeed an issue with One UI 4, I installed it again. And as expected, I am not getting VoLTE or WiFI calling again.

    Since I changed from Sprint to Airtel, I am not able to withdraw from the Beta program as well. I am getting the error "One UI beta features aren't available because your service provider has changed".

    Also, I am not sure what the final One UI 4 will offer. For the first time in my life, I am seeing an Android upgrade causing my phone to not able to connect to VoLTE.

    I am also attaching the screenshots of Phone Information. As you can see, in OneUI 3.1, VoLTE and WiFi calling are provisioned. But in OneUI 4, both are not available. I am assuming the issue is because IMS is not registered. But, I am not able to find how this can be fixed.

    Thanks in advance for your help.


    #volte #samsung #s21ultra #oneui #oneui4 #imsservice #ims #airtel #oneuibeta
    Hi, Thanks for your information that would help
    unfortunately I have waisted lot of time to find out the reason and U firmware helped, could you be so kind to check 1 thing if you are still on U1 ? and VoLTE is working? if yes please can you tell us if the phone number is visible in About Phone > Phone number?
    because on U1 firmware it was never being visible even on android 11
    Yeah, I have U1 model and volte does work now. However there's a bug if you are using volte wifi calling. In case, you connect your device to another wifi, volte goes away and only fix is to reboot the device. Regarding phone number, yeah I can see it in about phone.