Two. SIM-Xiaomi maps: how does Dual work SIM How to set up without errors

Xiaomi smartphones have long supported Dual SIM, the ability to use two SIM cards simultaneously on the same device, which is convenient for those who share work and personal numbers, travel often or want to save on roaming. However, not all users know how to properly configure two SIMs, avoid conflicts between them and optimize the network.

In this article, we will understand how technically implemented support for two SIM cards in Xiaomi smartphones, which models support Dual. SIM + MicroSD, how to set network and call priority, and solve typical problems – from lack of 4G on the second sim before conflicts with messengers. MIUI, which allow you to flexibly manage the work of two SIM cards without resetting to factory parameters.

How to support two SIM cards in Xiaomi: technical details

Xiaomi smartphones use two types of Dual SIM implementation:

• 🔄 Dual SIM Dual Standby (DSDS) — Both SIM cards are active, but only one can work on the network. 4G/5G, second-hand 2G/3G. This is the most common scheme in budget and medium-budget models (Redmi Note). 10/11/12, POCO X3/X4).
• 📶 Dual SIM Dual Active (DSDA) — Both SIM cards can work simultaneously in the 4G, But this technology is rare (for example, in Xiaomi 12 Pro or Mi 11 Ultra).

It is important to understand that even in DSDS-Both SIMs are physically connected to the communication module, but only one can be active at the same time. When you call the first SIM, the second one temporarily falls asleep and may miss the incoming call.

In hybrid slot models (SIM2 + MicroSD), the second slot can work with either a SIM card or a memory card - but not at the same time. Xiaomi does not block the use of MicroSD when installing two SIM cards, but requires a reboot of the device to change configuration.

What Xiaomi models support two SIM cards (list by series)

The vast majority of Xiaomi smartphones in recent years support Dual SIM, but there are nuances with hybrid slots and 5G support. Below is a table with the current series (data for 2026):

Please note: in the models with 5G-modem (e.g. Redmi Note 12 Pro)+) The second SIM card often only works in mode. 4G, even if the slot supports 5G. This is a hardware limitation and cannot be circumvented.

⚠️ Note: In Xiaomi smartphones for the Chinese market (noted) CN In the model, there may be no support for Russian LTE-Check the specifications on the official website before buying.

How to activate and configure two SIM cards in Xiaomi: step-by-step instructions

Once the second SIM card is installed, MIUI automatically detects it, but it requires manual adjustment to work properly.

1. Go to Settings. → SIM-maps and mobile networks.
2. Click on the name of the second SIM card (e.g. SIM 2).
3. Turn on the switch. SIM-map.
4. Please specify the name of the SIM card (e.g., “Worker” or “Personal”) for convenience.
5. In Network Type, select your preferred standard: 4G, 3G, or 2G (if you want maximum battery savings).

To set the priority of calls and SMS:

• 📞 B Settings → SIM-map → Default call select SIM card for outgoing calls.
• 💬 V SMS By default, specify a SIM card to send messages.
• 🌐 In Mobile data, select a SIM card for the Internet (you can enable Automatic selection, but this does not always work stably).

Make sure that both SIM cards are included in the settings

Give unique names for each SIM card

Select a SIM card for default calls

Set up mobile data for the desired SIM card

Reboot your smartphone after the changes-->

If one of the SIM cards is not determined after setting up, try:

1. Remove and re-insert the SIM card (check to keep the contacts clean).
2. Reset the device.
3. Reset network settings in Settings → SIM-map → Resetting network settings.

How 4G/5G works on two SIM cards: limitations and workarounds

The main problem when using two sim cards in Xiaomi is the restriction on simultaneous operation in 4G/5G. Most models (except flagships with DSDA) have the following rules:

• 📶 If SIM1 activated 4G/5G, piece SIM2 switching over 2G/3G.
• 🔄 When an active call is made on one SIM card, the second one is temporarily disconnected from the network (may miss the incoming call).
• 🚫 Only in mode. 2G both Sims at the same time 4G no-one will work.

To optimize the work:

1. Set the network priority for each SIM card manually, for example, if SIM1 is used for the Internet, set it to 4G and SIM2 to 3G.
2. Enable the option Volte (VoLTE) in Settings → SIM-cards → Call 4G. This will allow you to call the first SIM card without falling Internet speed.
3. For models with MIUI 14+, Double Call Wait (in some regions) is available, allowing you to receive incoming SIM cards even while you are talking on the first one.

⚠️ Note: In Xiaomi smartphones with Qualcomm Snapdragon processor (for example, POCO F5) activated 5G On the first SIM card, the second one can lose communication completely for a few seconds when switching networks.

💡

If it is critical for you to have both SIMs running in 4G, consider buying a DSDA-enabled smartphone (like the Xiaomi 13 Ultra).The alternative is to use eSIM for a second SIM (if the model supports).

Typical Two-SIM Card Problems in Xiaomi and Their Solutions

Even after you set it up properly, users are faced with typical problems, and we're going to look at some of the most common ones.

1.The second SIM card does not catch the network or constantly switches to 2G

Reasons:

• 📡 Weak operator signal (check coverage on provider's website).
• ⚙️ Wrong settings APN (particularly relevant MVNO-Operators of the type "Tele2" or "Yota").
• 🔋 Battery savings shuts off background activity of second SIM card.

Decision:

1. Check the settings. APN In Settings → SIM-map → [choose SIM] → Access points (APN). If necessary, add the parameters manually (the data can be taken on the operator's website).
2. Turn off the Adaptive Battery in Settings → Battery for the second SIM card.
3. Enable High Performance Mode in Settings → Special Opportunities → Performance Mode.

2. SMS does not arrive on one of the SIM cards

This is most often related to conflict. SMS-centers or message locks. Try it:

• 📩 Delete old messages (if memory is full).
• 🔄 Reboot the phone.
• 🛠️ Reset network settings in Settings → SIM-map → Resetting network settings.

3 Calls are dropped or are delayed

This is typical of DSDS models, where the second SIM card falls asleep during active connection on the first.

• 📞 Enable VoLTE for both SIM cards (if supported by the operator).
• 🔄 Turn off Wi-Fi Calling in Settings → SIM-map → Sometimes it conflicts with voice calls.
• 📶 Try to manually select the operator network in Settings → SIM-map → [choose SIM] → Network operators (automatic selection may fail).

How to Optimize Battery Consumption When Using Two SIM Cards

Two active SIM cards increase power consumption by 10-20% by continuously scanning networks to reduce the load:

• 🔋 Turn off AutoSearch Network for a Second SIM Card if it is rarely used: Settings → SIM-map → [choose SIM] → Searching the net → Manually.
• ⚡ Turn on Traffic Savings for Second SIM Card Background Data: Settings → SIM-map → Mobile data → Saving traffic.
• 📵 If the second SIM card is only needed for calls, set it to mode Only 2G — This will reduce battery consumption by 30%.
• 🛌 Use Sleep Mode for the second SIM card at night (setting is available in some custom firmware like Xiaomi.EU).

It is also worth turning off background data transfer for underutilized applications tied to the second SIM card.

Settings → Applications → Application Management → [select application] → Mobile data

⚠️ Note: In Xiaomi models with a MediaTek processor (for example, Redmi Note 11) simultaneous operation of two SIM cards in the 4G If the phone gets too hot in the antenna area, force the second SIM card to be limited to mode. 3G.

Hidden MIUI features for managing two SIM cards

MIUI contains several hidden settings that allow you to flexibly manage the Dual SIM.

1. Turn on Developer Mode by tapping 7 times on the MIUI version in Settings → About Phone.
2. Go to Settings → Additional → Developer settings.
3. Find the Network section and activate:

• 🔍 Display network information – displays the current communication standard (2G/3G/4G) for each SIM card in the notification panel.
• 📊 Mobile traffic statistics – allows you to track data consumption for each SIM card separately.
• 🔄 Quick switching SIM — Adds a button to change the SIM card directly into the notification curtain.

MIUI 14+ also introduced an experimental Dual SIM Dual VoLTE (DSDV) feature that allows VoLTE to be used on both SIM cards simultaneously, to enable:

Enter the phone code in the app: ##4636##


Go to "Phone Information" → "Settings" → "Enable DSDV"

This feature does not work on all models and can cause modem malfunctions. Before activation, back up your data!

FAQ: Frequent questions about two SIM cards in Xiaomi