How to register IMS-Xiaomi service: from VoLTE to VoLTE HD-call-up

If your Xiaomi does not support VoLTE or VoWiFi, and the operator claims that the service is connected, the problem most often lies in the inactive system. IMS-This protocol is responsible for the transmission of voice through the LTE/5G And Wi-Fi, which provides stable connectivity even in low-cost areas. POCO Registration is not always automatic.

In this article, you will find the most relevant ways of forced activation. IMS firmware MIUI 14/15 (including HyperOS), as well as solutions to common errors such as "Not registered on the network" IMS" We'll look at both software methods (through settings and engineering menus) and hardware checks, from SIM cards to regional restrictions. FAQ-A block at the end with responses to frequent cases.

What is it? IMS Why it doesn’t work for Xiaomi

IMS (IP Multimedia Subsystem is a standard for transmitting voice and video calls over Internet protocols (LTE, 5G, Wi-Fi, without it, modern functions like:

• 📞 VoLTE (voice by voice) 4G/5G)
• 📶 VoWiFi (calls via Wi-Fi)
• 🎤 HD-voice (increased sound quality)
• 🔄 Quick switching between networks

They will not be available even if your plan supports them.

Xiaomi has problems with IMS arise from several reasons:

• ⚙️ Lack of registration on the network (often after a reset or update)
• 🌍 Regional restrictions (firmware for China/India may block the IMS Russia)
• 📱 Incompatible firmware (castom or outdated versions) MIUI)
• 🔌 Hardware problems (damaged modem or antenna)

Before you start setting up, make sure that:

1. Your tariff supports you. VoLTE/VoWiFi (check with the operator).
2. SIM card activated in LTE/5G-networking 2G/3G).
3. The device is not locked for a specific operator (e.g., China Mobile phones).

Check of current status IMS Xiaomi

Before you register, you need to make sure that the service is really inactive.

1. Open the dial and type: ##4636## On some models (POCO X5, Redmi Note 12 may need to be entered: ##36446337##
2. In the menu that opens, select Phone Information → Settings IMS.
3. Check the lines: IMS registration must be Registered (if Not Registered, service is disabled), VoLTE provisioned - 1 (active) or 0 (inactive). VoWiFi provisioned - similarly.

If menu 4636 does not open:

• 🔧 Try another code: ##36446337## MIUI 14+).
• 📱 Install the NetMonster app (shows status) IMS real-time).
• ⚠️ Some of the firmware (e.g., HyperOS for the POCO F5) Engineering menu is blocked - you will need to unlock the bootloader.

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If nothing happens after you enter the code, restart your phone and try again. (Xiaomi) 13T) Engineering menu opens only after connecting to Wi-Fi.

Method 1: Registration IMS via settings MIUI

On most Xiaomi devices, including the Redmi Note 11, POCO X4 Pro, Mi 11) IMS activated through standard settings. Follow the instructions:

1. Go to Settings. → SIM-maps and mobile networks.
2. Choose yours. SIM-card (if there are several).
3. Activate the switches: VoLTE (may be called "Voice on the Voice") LTE" Or "Enhanced Calls" VoWiFi (wi-fi calls).

Reset the device.

If the switches are missing or gray:

• 🔄 Update your firmware to the latest version (via Settings) → The phone. → Updating the system).
• 📋 Check if your model supports you. IMS (For a full list of compatible devices, see the table below).
• 🌐 Make sure the region of the phone matches the region of the SIM card (for example, firmware for India may not work with Russian carriers).

Update the firmware to the latest version

Check the support of VoLTE operator

Make sure that SIM-card in slot 1 (main)

Enable data transmission to SIM-map

Reboot your phone after the changes-->

After activation, wait for the notification "IMS Registered (may take up to 5 minutes) If not, proceed to the next method.

Method 2: Compulsory registration through the engineering menu

If the standard settings don’t help, try registering. IMS manually via the engineering menu (works on most Qualcomm Snapdragon devices).

1. Open the dial and type ##36446337## (Mediatek may need #36446338###).
2. Go to Phone Information (or Phone Information).
3. Scroll down to the section. IMS Settings.
4. Press Turn On. IMS (or Enable IMS).
5. Next, choose IMS Registration → Register.
6. Wait for Registered status to appear (it can take up to 2 minutes).

If the Register button is inactive:

• 🔧 Try changing. IMS Mode on IMS over LTE or IMS over WiFi.
• 📶 Make sure the phone is connected to LTE/5G (In the network status, it should be LTE or NR, not H+).
• ⚠️ On some firmware (HyperOS for Xiaomi 14), the engineering menu may require root rights.

Method 3: Reset network settings and re-registration

If IMS If you don't log in despite all the effort, try resetting your network settings, which will delete stored Wi-Fi networks and mobile Internet settings, but often solves registration problems.

1. Go to Settings. → SIM-maps and mobile networks → Additionally. → Resetting network settings.
2. Confirm the reset (entry will be required) PIN-code SIM-map).
3. After restarting manually enable: Data transfer for SIM-- The card mode. 4G (LTE) or 5G in network settings. VoLTE and VoWiFi (if switches are available).

Wait for automatic registration IMS (It can take up to 10 minutes).

If the dumping didn't help:

• 🔄 Try re-installing. SIM-card in another slot (on two-symbol devices) IMS Sometimes it only works in slot 1).
• 📱 Check if custom firmware (like LineageOS or Pixel Experience) is installed – it may not support custom firmware. IMS.
• ⚠️ Make sure your phone doesn’t activate flight mode or energy saving (they block registration).

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Network resets are the most reliable way to fix software failures IMS, It also removes all stored Wi-Fi passwords and VPN-Preserve them in advance!

Resolving of registration errors IMS

If after all the manipulations IMS still not registered, pay attention to typical errors and their solutions:

Pay particular attention to regional constraints, such as:

• 🇨🇳 Phones with firmware for China (China) ROM) often IMS Russia.
• 🇮🇳 Devices for India may have VoWiFi restrictions.
• 🇪🇺 European firmware (EEA ROM) They are usually compatible with Russian operators.

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If you bought a phone in China or on AliExpress, it is likely to be China. ROM. To activate IMS, You will need to re-flash the device on Global. ROM (instructions are available on the forums 4PDA or XDA Developers).

Compatibility of Xiaomi devices with IMS (VoLTE/VoWiFi)

Not all Xiaomi smartphones support IMS. Below is the compatibility table of popular models (relevant to the MIUI 14/15 hyperos):

If your model is not on the list:

• 🔍 Check the specifications on the official Xiaomi website (section "Network & Connectivity").
• 📱 Check with the operator if your device supports VoLTE/VoWiFi on-line.
• 💬 Look for feedback on forums (for example, 4PDA) — Users often share their experience of activation IMS rare-model.

FAQ: Frequent questions about registration IMS Xiaomi