[Xiaomi Redmi Note 3 Questions & Answers] Beliares:
Hello everyone,

Let me begin with saying that i've already contacted MIUI support as well as i've searched other MIUI forums for the solution of my problem, wich is really strange to be honest.

I own an original Redmi Note 3 Pro (previously i owned a Redmi Note 3G). I use the largest mobile network operator in my country and he gives all his customers the ability to use other mobile network operators range/connection in roaming for free whenever we like. It doesn't support 4G from different vendors, so it's 3G max. This is important factor later in the story.

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The phone was originally shipped with MIUI China Stable ROM wich run fine but as you know it had a lot of crap in it including adds and a lot of wierd chinese apps. But it DIDNT'T cause my any trouble with phonecalls quality.

I used MIflash & download mode to flash the latest MIUI Global Stable ROM, wich in the beginning didnt cause me any problems with phonecall quality.

HOWEVER. After 1 week of using the phone, one of the updates for Global Stable came out. Phone was updated without any problems and it run fine, but i noticed that whenever im talking with someone the quality of the phonecall was lower then ussually.

Then another update came out and it was EVEN WORSE. I thought it's the issue with the ROM itself so i patiently waited to get my permissions for unlocking the device.

I finally got it so i flashed my phone with MIUI China DEV ROM, installed TWRP and installed the latest MIUI available for my country (wich i previously used for over 2 years or RN 3G) wich also includes fixes and optimizations. HOWEVER the problem still occured.

I then started to blame my SIM Card, so i got a new one yesterday, i also did a factory reset just to be sure, DIDN'T HELP.

So to SUM UP:

Issues: Call quality is low in random calls

How does it show: Caller speaks like with a robotic voice, interference, sometimes i don't hear the caller for 2-3 seconds.

ROM STORY:

1. I purchase RN3 Pro. It comes with original china stable ROM. Phonecalls work fine.

2. I install global stable. Phonecalls are fine.

3. I install two updates to global stable - the quality of phonecalls goes down.

4. I unlock bootloader and install custom ROM along with TWRP, same issues.

5. I reflash whole ROM, clean installation, same issues.

6. Yesterday : I get new SIM card, i factory reset my system and get new updates: SAME ISSUES.

Wierd factors:

- sometimes when the problems occurs while on call, i can resolve the issue with just waking up the screen for a couple of seconds..

- problem seems to happen less when WIFI/Data usage are off

- problem seems to happen less when using headphones (Piston V3)

- problem DOESN'T happen AT ALL when i switch to other mobile operator network in roaming! It's only happening in my main mobile operator network! I would use other networks instead of mine but LTE/4G isn't allowed yet while on roaming :/

- this issue happens on both SIM CARD slots, on different SIM CARDS

I tried to reflash China Stable, however it seems that there were too many updates and one of them is causing the problem now on every ROM. There's a few topics on MIUI Official forums about that, there are bug reports about that but i doubt MIUI Devs will notice this.

Does anyone have any idea what could be causing this?

Link to my MIUI topic: http://en.miui.com/thread-267736-1-1.html

Link to random bug report about this from other user: http://en.miui.com/forum.php?mod=viewthread&tid=266620&page=1#pid4845168

Kind regards,

Beliares