How to turn on VoWiFi on Xiaomi Mi 9: full instruction with solutions

Xiaomi Mi 9 is the flagship of 2019, which is still relevant thanks to the powerful hardware and support for modern communication protocols. One of the most useful but often ignored features is VoWiFi (Voice over Wi-Fi), which allows you to call over Wi-Fi network instead of cellular. This saves in areas with poor coverage, saves battery power and even improves voice quality. However, on the Mi 9, it often has difficulties: it may not be on the menu, it suddenly turns off or works unstable.

In this article, we'll not only show you how to turn on VoWiFi on the Xiaomi Mi 9, but we'll also take a look at all the pitfalls, from checking carrier support to manual activation through the engineering menu. And you'll also learn why the MIUI update can go missing and how to get it back. If you've tried to turn on VoWiFi but failed, here's a solution to 90 percent of the typical problems.

What is VoWiFi and why is it needed on Xiaomi Mi 9?

VoWiFi (or Wi-Fi Calling) is a technology that allows you to make calls over the Internet, connected over Wi-Fi, instead of the traditional cellular network. On the Xiaomi Mi 9, this feature runs on the basis of the IMS standard (IP Multimedia Subsystem), which is integrated into modern versions of MIUI. The advantages are obvious:

• 📶 Stable signal even where the cellular network is weak (basements, remote areas, thick walls).
• 🔋 Battery savings: the phone does not waste energy on finding a cell tower.
• 🎙️ Better sound quality thanks to codec HD Voice (if supported by the operator).
• 🌍 International calls at home region rates (if the operator allows it).

First, not all Russian carriers officially support VoWiFi on Xiaomi (more in the table below). MIUI. Third, it requires active work. SIM-support-card IMS (Even if the calls are via Wi-Fi).

If you're in a lot of places with poor coverage or traveling, VoWiFi is a real lifesaver, but before setting up, make sure your carrier doesn't block this feature - more on that.

Checking your operator’s VoWiFi support

Before you try to enable VoWiFi on Xiaomi Mi 9, you need to make sure that your mobile operator supports this technology. In Russia, the situation is ambiguous: some providers officially declare support, but in practice the feature may not work due to limitations at the level of the service. SIM-card.

Here is the current table of VoWiFi support by the main Russian operators (data for 2026):

If your carrier is not listed or you use a virtual provider (such as Tinkoff Mobile or SberMobile), the chances of VoWiFi working are minimal, and you can try alternative solutions like Google Fi (if you have a US SIM) or applications like Skype/WhatsApp for Wi-Fi calls.

⚠️ Note: Even if the operator supports VoWiFi, on the Xiaomi Mi 9, the function can be blocked at the firmware level. MIUI 12.5 and MIUI 13 for Russia VoWiFi hidden in the engineering menu.

Step-by-step: how to turn on VoWiFi on Xiaomi Mi 9

If your carrier supports VoWiFi and your phone has the latest version of MIUI installed, you can turn on the function in the standard way.

1. Open the Settings app (the gear icon on the home screen).
2. Go to section. SIM-maps and mobile networks.
3. Choose yours. SIM-card (if two of them).
4. Slip on the item Calls via Wi-Fi (or Wi-Fi Calling).
5. Activate the switch to the position VL.
6. Confirm the activation if a request from the operator appears.

When activated, the status bar (top right corner of the screen) will show up with a VoWiFi or Wi-Fi Calling icon, and if it's not, the function doesn't work, in which case, try the following steps:

Reboot the phone.|Check the Wi-Fi connection|Update. MIUI last-minute|Reset network settings (Settings) → Memory. → Reset → Resetting network settings)|Try another one. SIM-map-->

If Wi-Fi Calls are not on the menu at all, your version of MIUI does not support VoWiFi at the interface level, and you will need to use the engineering menu or USSD codes, which is discussed in the next section.

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Before turning on VoWiFi, make sure that the phone has the latest firmware installed. Go to Settings → About Phone → System Update.

Activate VoWiFi via the Engineering Menu (if there is no option in the settings)

On some versions of MIUI (especially on the Xiaomi Mi 9 with firmware for Russia), the VoWiFi option is hidden, in which case it can be turned on via the engineering menu (MTK Engineering Mode or Qualcomm Service Menu, depending on the processor).

1. Open the Phone app and enter the combination: ##4636## This will open the Testing menu.
2. Go to the Phone Information (or Phone Information) tab.
3. Scroll down to the Wi-Fi Calling or IMS Status block.
4. If you have an Enable VoWiFi option, activate it.
5. Go back to the basic settings and check if the Calls item appears via Wi-Fi.

If #4636### doesn’t work, try an alternative method:

1. Install the MTK Engineering Mode (for MediaTek) or Qualcomm Service Menu (for Snapdragon) from Google Play.
2. Open the app and go to the Telephony or Connectivity section.
3. Find options related to IMS or VoLTE/VoWiFi and activate them.

⚠️ Warning: Changes in the engineering menu can lead to unstable network operation, if after activation of VoWiFi mobile Internet is lost or stopped coming SMS, Reset the network settings (Settings) → Memory. → Reset → Resetting network settings).

If the engineering menu didn't work, the last option is manually editing IMS settings through ADB, which is more complicated, but works 90 percent of the time.

Manual activation of VoWiFi via ADB (for power users)

If the standard methods didn’t work, you can try turning on VoWiFi via Android Debug Bridge (ADB), a method that requires a computer and basic command line knowledge, but gives you maximum control over IMS settings.

Here's the step-by-step instruction:

1. Download and install on your PC Platform Tools (part of the Android SDK).
2. On your phone, turn on USB Debugging: Settings → About Phone → MIUI version (tap 7 times to unlock Developer Settings), then go back to Settings → Additional → Developer → Debugging by USB.
3. Connect Xiaomi Mi 9 to your computer via USB and confirm the debugging permission.
4. Open the command line (Windows) or the terminal (macOS/Linux) In the folder with the platform-tools and execute commands in order: adb shell settings put global wifi_calling_enabled 1 settings put global wifi_calling_mode 1
5. Reboot the phone.

If VoWiFi does not work after the restart, try additional commands to force activation of the IMS:

adb shell


am start -n com.android.phone/.settings.WifiCallingSettings




am broadcast -a android.intent.action.WIFI_CALLING_SETTINGS_CHANGED

These commands simulate opening VoWiFi settings and send a signal to the system to change the configuration, and if that doesn’t work, the last option is VoWiFi-enabled firmware (such as MIUI EU or Pixel Experience).

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ADB-The commands only work on the unlocked bootloader. If you have official Xiaomi firmware with a locked bootloader, this method will not work.

Frequent VoWiFi issues on Xiaomi Mi 9 and their solutions

Even if you manage to turn on VoWiFi, the function can be unstable, and here are the most common problems and ways to fix them:

• 🔄 VoWiFi spontaneously shuts down: Check if Wi-Fi is off while sleeping (Settings) → Wi-Fi → Additionally. → Connect to Wi-Fi during sleep → Also make sure that the phone does not activate the power saving mode for the Phone application.
• 📵 There is no VoWiFi icon, but calls are made via Wi-Fi: This is normal for some carriers (like Yota), the main thing is that calls pass## → Phone information → Wi-Fi Calling Status.
• 🚫 Operator blocks VoWiFi on Xiaomi: Try inserting SIM-The card is in another phone (like an iPhone or Samsung) and you turn on VoWiFi there. If it works, the problem is in the firmware of the Mi 9. MIUI EU or Global ROM.
• 🔊 Interviewer can't hear or hear the robot: This is a sign of codec incompatibility. Turn off VoWiFi and use standard calls or switch to VoLTE (if supported).

If none of these methods helped, contact the operator’s support to check the profile. IMS yours SIM-Sometimes the problem is with the outdated settings on the provider side.

VoWiFi Alternatives: How to Call Over Wi-Fi Without Official Support

If your carrier does not support VoWiFi or the Xiaomi Mi 9 feature is fundamentally not working, you can use alternative ways of calling over Wi-Fi:

• 📞 Google Voice: It works in the U.S. and some other countries, it requires a registration and a U.S. number, and the quality of the connection is stable, but there are delays.
• 💬 WhatsApp/Telegram/Viber: Calls via messengers will not replace the usual calls (there will be no integration with the phone book), but will save in emergency cases.
• 🌐 Skype: Supports calls to regular numbers (paid), but the quality depends on the servers of Microsoft.
• 📡 Local. SIP-Customers: Apps like Zoiper or Linphone allow you to call over Wi-Fi, but require settings SIP-Account (suitable for corporate users).

The most versatile option is WhatsApp, as it works almost everywhere and requires no additional settings.

• They are not displayed in the phone call log.
• They can be blocked by some operators (e.g. in the UAE or China).
• They also require that the interlocutor use the same messenger.

If it is critical that calls go through the standard Phone app and appear in the log, you just have to wait for the operator to add VoWiFi support for the Xiaomi Mi 9, or change your device to a newer one (for example, Xiaomi 13, where VoWiFi works out of the box).

FAQ: answers to frequent questions about VoWiFi on Xiaomi Mi 9