How to make a default phone on Xiaomi Redmi: SIM-cards, calls and SMS

Why Xiaomi Redmi can’t choose the default phone?

You put two in. SIM-cards in Xiaomi Redmi, but the smartphone persistently rings from the “wrong” SIM or duplicates SMS Or does it prevent you from choosing the primary number for the mobile Internet? The problem is familiar to many owners of devices with a hybrid slot (where the second one is not used at all). SIM Competing with a memory card or after an update MIUI In this article, we'll look at all the ways to assign a phone by default, from basic settings to hidden firmware chips.

Feature of Redmi (unlike the flagship Xiaomi or POCO) — often-cut-down SIM-For example, in budget models like Redmi. 9A or Redmi Note 10 There may be no option to select a SIM for 4G/5G It's separate from voice calls. K50 s MIUI 14 The algorithm for distribution of traffic between SIM-The maps have changed, and now priority depends on the network mode (auto/manual.

Method 1: Standard settings SIM-card MIUI

Let’s start with the most obvious: the management menu. SIM-This method works for all Redmis with maps. MIUI 12 and newer, but the interface may vary slightly depending on the firmware version:

1. Open the settings (cog icon on the desktop).
2. Go to section. SIM-Maps and mobile networks (or connections) → SIM-maps in new versions).
3. Tap by name. SIM-maps, for example, SIM 1: MegaFon).
4. Select the item Type of use SIM-map.
5. Put the boxes in front of you: 📞 Default calls – for outgoing calls. 💬 SMS by default - to send messages. 🌐 Mobile data for the Internet (if necessary) 4G/5G on this sim).

If the option Type of use SIM-There is no map, so your Redmi model doesn't support separate function assignments.

Use the original firmware MIUI (customless)|Both SIM-Cards are active and recognized by the system|No SIMs. PIN-Code (can block settings)|The slot is not damaged (try to move the cards in places)-->

Method 2: Manual assignment of SIM for calls and SMS

In some versions of MIUI (especially on the Redmi Note 8 Pro, Redmi 9T), the default option is hidden behind additional actions.

1. Open the phone application (pipe icon).
2. Click on the three dots in the upper right corner → Settings.
3. Choose. SIM-call-card.
4. Please indicate preferred SIM for: 📱 Outgoing challenges. 📥 Incoming calls (if you need to redirect to one SIM).

Communications

Settings → SIM-card SMS

Important: On a Redmi with a hybrid slot (for example, the Redmi Note 11), priority is given SIM-card in slot 1, even if you chose the second SIM by default. This is a hardware limitation - check the location of the cards physically.

SIM 1 (first slot)|SIM 2 (second slot)| Depends on the situation | I don't know how to check-->

Method 3: Set up mobile internet (4G/5G)

If you want to assign a default phone to the mobile Internet instead of for calls, the algorithm is different. Here, it's important to consider network mode and support for VoLTE (voice over 4G).

1. Go to Settings. → SIM-maps and mobile networks.
2. Choose. SIM-The map you want to make the main one for the Internet.
3. Activate the mobile data switch.
4. Tap the network type and select: 📶 4G (preferably for maximum speed. 📡 3G — if 4G It's not catching, but you need calls. 🔄 Auto – if you want the system to choose itself.

VoLTE

On Redmi with MIUI 14 Double function appears 4G (Dual 4G), permitting SIM-maps simultaneously work on the network 4G. It is only available on Snapdragon models. 8xx (Like Redmi. K60 In budget devices (e.g. Redmi) 12C) When activating the mobile Internet on one SIM The second automatically goes into the mode 2G.

Problems and mistakes when choosing a default phone

Even after setting up correctly, Xiaomi Redmi can ignore your preferences.

⚠️ Attention: Redmi with Android 13 (MIUI 14) after resetting the settings to the factory settings SIM-The cards are reset to default values, and if you use two SIMs, you'll have to reset their priority!

Features of hybrid slots (SIM + microSD)

Many Redmi models (e.g. Redmi 10A, Redmi Note 11S) feature a hybrid slot where the second SIM and memory card share the same slot.

• 🔄 If you have a microSD, the second one is SIM-The card will not be available (and vice versa).
• 📱 In some models (e.g. Redmi). 9C) slot SIM 2 only supports only one thing. 2G, even if it's installed in it 4G-map.
• 🔋 In the case of two SIM Without microSD, battery consumption increases by 10-15% due to continuous scanning of two networks.

If both are critically important SIM-You'll have to sacrifice your memory card, and the alternative is to use cloud storage (Mi Cloud, Google Drive) or OTG-flash-drive adapter.

💡

Before buying Redmi, check out the slots scheme on Xiaomi's official website. For example, the Redmi Note 12 Pro+ has separate slots for two SIMs and a microSD, while the Redmi 10 has a hybrid.

Additional settings for advanced users

If the standard methods didn’t work, try these hidden MIUI features:

• 🔧 Codes USSD reset SIM: ##4636## → Phone information → Settings SIM You can manually specify the priority SIM for voice and data here.
• 📡 Manual Network Selection: Sometimes Automatic Mode (LTE/3G/2G) You can't just try to pick your own hand. LTE basic SIM.
• 🔄 Slot switching: Some Redmis (like the Redmi Note 10 Pro) can change slot logic numbers via the engineering menu. Type ##36446337## and select BandMode → SIM Switch.

⚠️ Note: Using the engineering menu (#36446337##) may cause network settings to fail. Write down current settings before experimenting or back up Settings. → Additionally. → Backup.

💡

If your Redmi does not save your settings SIM After restarting, this is a sign of a module failure. IMS Service. Solution: Update your firmware or reset your network settings to Settings → SIM-map → Resetting network settings.

FAQ: Frequent questions about setting up SIM on Xiaomi Redmi