Galaxy Note 10+ SM-N975F – microphone not working during cellular calls on iodeOS 7.5

System and Apps
1

Hello,

after updating my Samsung Galaxy Note 10+ from iodeOS 4.3 to 7.5, the built-in microphone stopped working during normal cellular calls.

Symptoms:

  • During GSM/mobile calls, the other person cannot hear me.

  • Speaker/audio output works normally.

  • Signal and network registration are fine.

  • Wired/Bluetooth headsets work correctly.

  • Voice recording and microphone access in apps work normally.

The issue appeared immediately after upgrading to iodeOS 7.5.

I already contacted support and was advised to ask the community whether others can reproduce this issue on Samsung devices / Note 10+.

Questions:

  • Has anyone experienced similar microphone issues during calls on iodeOS 7.x?

  • Is this related to VoLTE / IMS / modem firmware?

  • Are there recommended modem/baseband versions for the Note 10+?

  • Did anyone find a workaround or fix?

Device:
Samsung Galaxy Note 10+

iodeOS version:
7.5

Thanks.

2

You can check the VoLTE registration by using *#*#4636#*#* and then going to “Phone Information v2 > IMS” or “Phone Information > 3 Dots > IMS Status”. BUT as I think I mentioned on email support (or intended to), VoLTE is not supported on any Samsung device due to them blocking it on all custom ROMs, so all that will show is that it isn’t available I think.

How recently were voice calls working with v4.3? Was that just immediately before, or instead had you not used it for a while?

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3

Hi Rik,

First of all, I need to correct what I said about the microphone.

The microphone works, but my voice comes through very quietly, and the call gets cut off—or rather, it’s choppy.

This problem only started after the update to Iode OS version 7.5.

Attached is the requested screenshot of my SIM connection settings.

Screenshot_20260529-155849_Einstellungen
Screenshot_20260529-155849_Einstellungen720×1520 80.2 KB

4

If this summary is accurate, then Sunrise finished shutting down its 2G and 3G networks some time ago.

With no VoLTE, and with no 2G or 3G networks to fall back to, it’s no surprise you’re having problems with calls on a Samsung.

5

Hi Taurus,

Thank you very much for your comment.

But if it’s a network issue, why does it work with Bluetooth headphones?

6

So, call audio works with headphones?

No idea why that might be, unless there’s maybe some unpublicized residual 2G remaining in your area that your device happens to connect to under certain conditions. I’ve seen a few forum comments about problems with Sunrise on other phone brands, so it could just be a carrier quirk. (Problems also reported here.)

But you’re definitely going to have continuing issues with Samsung unless the current work-in-progress reverse engineering of their IMS code is successful.

7

Hi Taurus,

I should mention that I was using Spusu until recently. But I had the same issues with Spusu.

I’m no expert on smartphone operating systems, but what I can do is use a process of elimination.

I updated from 4.3 to 7.5. Everything was working fine up until then. But after the update, it stopped working. It can’t be that Spusu (Salt) and Yallo (Sunrise) both disabled something on the exact same day, leaving me unable to use my phone. Above all, I want to emphasize that the connection with Bluetooth headphones works without any issues. So it can’t be due to any network problems.

8

To summarize my observations so far in as structured a way as possible, I used ChatGPT to help me organize the information. The following points are based on my own tests and observations of the device:

Additional technical observations regarding the issue:

* During an active cellular call, the device switches from LTE to H+.

* Calls are therefore apparently routed via 3G (CSFB) and not via VoLTE.

* The Galaxy Note10+ (SM-N975F) is fundamentally VoLTE-capable and should, in theory, be able to make calls without 3G.

* However, under iodéOS 7.5, VoLTE does not appear to be used, as the connection switches to H+ during every call.

Observations on voice quality:

* The other party consistently hears me very quietly and choppily through the internal microphone.

* I hear the other party normally.

* The connection remains stable and does not drop.

Elimination tests:

* The problem does not occur with a Bluetooth headset. The other party hears me normally.

* The same SIM card was tested in a Samsung Galaxy Note 3. Mobile calls work there with normal voice quality.

* The Note 3 does not use VoLTE and makes calls via the existing 3G network without any issues.

* As a result, the SIM card, phone number, network coverage, and a general disruption of 3G telephony appear rather unlikely as the main cause.

Additional relevant information:

* The problem only occurred after the update to iodéOS 7.5.

* The behavior is identical on both the Sunrise and spusu/Salt networks.

* Voice recorder, Signal calls, and Signal voice messages work flawlessly.

* The internal microphone therefore appears to be functioning correctly.

Additional question:

I purchased the Galaxy Note10+ directly from iodé. If the cause is indeed the lack of VoLTE functionality or the 3G shutdown, I would be interested to know how this aligns with iodé’s official support and distribution of the device.

My conclusion:

Since the behavior changes depending on the audio source used (internal microphone vs. Bluetooth headset) and the same SIM card works without issues in a Note 3 for 3G calls, I suspect a problem in the Note10+’s call audio path under iodéOS 7.5 rather than a pure network issue.

Possible areas to investigate include:

* Audio routing

* Microphone selection

* Microphone gain

* Noise suppression

* Audio HAL

* Device-specific telephony audio configuration

Additionally, it is notable that despite its VoLTE capability, the device falls back to H+ during calls, which could potentially indicate a separate IMS/VoLTE issue.

9

AI is certainly prolific in writing diatribes!

Samsung blocks VoLTE on all Samsung devices that do not have their stock firmware, this has been true for some time, and is noted in our official devices page: iodéOS official supported devices - iodé So in this case you should contact our support email to request a device return / exchange.

To Sunrise configuration, please see this writeup that solves the issues (but again your issue is having a non-VoLTE capable device and a carrier that has discontinued 3G calls I think).

10

If this is only a VoLTE issue, why does the microphone work during calls when using a wired or Bluetooth headset, but not with the built-in microphone?

11

It may be more than a VoLTE issue, there was another report / discussion I recall recently with a user having similar challenges that I am not recalling if they were sorted out or not.

But certainly you will not get VoLTE with a Samung device, unfortunately. While you may be in the situation now of having some 3G / 2G coverage from some of the towers, once those networks are fully decommissioned, the device simply will not be able to make 4G / 5G voice calls :frowning:

12

And what about this?

Open-source SIP/IMS stack for LineageOS, based on phhusson/ims for Samsung devices …

1 Like
13

!! I passed this to @vince31fr in our team discussion !!

1 Like