How to Set Up Second Line on Xiaomi: Dual SIM and eSIM

Modern Xiaomi and Redmi smartphones have long ceased to be just devices for calls, turning into powerful multimedia centers, where the presence of two active numbers has become the de facto standard. Users often share personal and work contacts, or use SIM cards of different operators to save on tariffs and roaming, which requires competent system configuration. Flagship models of the brand have been equipped with full support for Dual SIM Dual Standby technology, which allows both numbers to stay online at the same time without the need for manual switching.

However, even with the advanced MIUI shell or the new HyperOS, owners may have difficulty assigning roles to SIM cards, especially when switching from other devices. Proper slot configuration affects not only the stability of voice communication, but also the speed of mobile Internet, as in some modes of operation one of the cards may temporarily lose access to the 4G/5G network during a conversation. In this guide, we will discuss all aspects of activation, setting priorities and using virtual SIM cards.

It is worth considering that the physical location of slots and the logic of the software can vary depending on the specific model of your device. Budget Redmi series sometimes have a combined slot that requires a choice between a second SIM card and a microSD memory card, whereas flagships Xiaomi and Poco F series usually offer two full-fledged nano-SIM slots. Understanding these nuances will help to avoid situations when after installing the card, the device stops seeing the drive or vice versa.

Preparation for installation and compatibility check

Before you start software setup, you need to make sure that your SIM card and device tray are physically compatible.Most modern Xiaomi smartphones use the Nano-SIM format, which is the smallest of the existing standards.If your SIM card is larger or cut by hand with an adapter, there is a high risk of getting stuck or damaging the contact group, which can lead to expensive repairs.

It is also critical to check whether your model supports two SIM cards simultaneously on fourth-generation networks. Some budget devices can provide Internet only on one of the cards, putting the second in 2G/3G mode during an active session, you can find out the exact characteristics in the specification on the official website or in the settings menu, which displays the current type of network for each slot.

• 📱 Make sure that both SIM cards are activated by the operator and do not have locks on the device. PIN-code, unless you plan to enter it every time you turn on.
• 🔌 Wipe the SIM card contacts with dry soft cloth before installation to rule out oxidation and signal loss.
• 📶 Check your operator’s coverage area as in some regions the second slot may perform worse due to the antenna design features.

Owners of devices purchased in China for use in the global market should pay attention to frequency support. Global versions of Xiaomi usually have a full range, but Chinese firmware may have software limitations or features displaying network status. Chinese versions of smartphones often do not support eSIM technology, so if you need a virtual card, make sure you buy a global version of the device.

⚠️ Warning: Never try to retrieve the SIM card tray while the device is on unless the hot replacement feature is activated (although modern smartphones allow it, the risk of static discharge or power controller failure is always there). It is best to manipulate the tray, having previously turned off the phone or making sure that the screen is turned off and the processes are not active.

Physical installation of SIM cards in the tray

The installation process begins with the removal of the tray, which uses a special clip that comes with a kit, or a thin needle. At the end of the smartphone there is a small hole in which you insert the tool perpendicular to the body and press until you click. The tray will be pushed out, and it can be carefully removed with your fingers, trying not to damage the rubber seal that protects the internal components from moisture and dust.

Notice the diagram shown on the tray itself or on the screen of the smartphone when first turned on, which shows the correct position of the chip. In two-symbol Xiaomi devices, the contacts are usually downward, but the location of the notch (skosa) on the plastic-based SIM card must strictly correspond to the shape of the recess in the tray. Forced installation can break plastic guides.

Once the cards are placed in the respective slots (SIM 1 and SIM 2), the tray is gently inserted back until the characteristic snap of the lock. If the tray does not enter to the end, do not press the force - perhaps it is inserted by the wrong side up or the SIM card has shifted. The system should automatically identify new cards and start the process of activating them, which will take a few seconds.

Primary Dual SIM setup in MIUI and HyperOS

Once the SIM card is installed, the system will suggest customizing the use of the SIM card, and the initial screen will allow you to assign names to SIM cards (e.g., Work, Home, MTS, Beeline) for easy identification later on, which is especially useful if you use SIM cards from different operators so as not to confuse which number will be called.

Settings menu → SIM-Maps and mobile networks (or two) SIM-The cards and the mobile networks are where the main switches are located, and you can activate or deactivate each of the slots independently. If you want to temporarily disable one of the lines so that it does not receive calls, it is enough to simply transfer the corresponding slider to the "Off" position without removing the physical card.

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Assign SIM cards clear names and choose different colors for each of them – this will allow you to instantly visually determine which line is used for a call or message, just by looking at the lock screen or call log.

An important parameter is the setting of the preferred network type. For each slot, you can choose the mode of operation: 5G preferably, 4G preferably or only 3G/2G. It is recommended to set the “5G/4G” mode for the main SIM card to ensure maximum data transfer speed, while for the second card, used only for calls, you can leave an automatic choice.

Set up the Internet and Prioritize Challenges

One of the most important tasks when using two numbers is to correctly allocate roles: which card is responsible for mobile Internet and which is responsible for voice communication. In Xiaomi smartphones, the default Internet works on only one selected SIM card, although both can accept calls. You can switch the card to access the network from the same SIM card settings menu, selecting the Internet by default.

To manage voice calls, the system offers three options: always ask when dialing, use the default primary SIM card, or assign a specific SIM card for all outgoing calls. If you often call different contacts from different numbers, the best way to leave the "Always Ask" mode, which allows you to select a SIM card right at the time of making a call.

There is also a feature called "Data Switching when you call", which is useful if your second SIM card does not support VoLTE technology. When you are actively talking on the main card, the Internet on it can switch to 3G, and in order not to interrupt page loading or navigation, the phone will automatically switch mobile data to the second SIM card.

Using eSIM technology on Xiaomi

eSIM technology (embedded) SIM) It allows you to use a virtual SIM card without the need for a physical tray, making room for a second physical Nano-SIM or memory card. On Xiaomi devices, eSIM support is implemented in most global flagships, starting with the Xiaomi 12 series and later, as well as in some mid-range models. QR-code provided by the operator.

The connection process is as follows: in the SIM card settings menu, the option "Add mobile tariff" or "Add eSIM" is selected. QR-The code will then start uploading the operator profile, which can take anywhere from a few seconds to a couple of minutes depending on the speed of the Internet and the load of the operator's servers.

⚠️ Note: When you reset your smartphone to factory settings, eSIM profiles can be deleted depending on the reset option chosen. Before selling the device or sending it for repair, be sure to delete the eSIM profile through the settings menu or contact the operator to unblock it to avoid blocking it.

One of the main advantages of eSIM is the ability to store multiple profiles at once, although only one can be active at a particular time (paired with a physical SIM card), which is ideal for travelers who can buy fares in advance from different countries and switch between them in a couple of clicks without looking for stores with SIM cards.

Advanced settings and communication optimization

For advanced users, features are available in the engineering menu and additional settings to fine-tune network behavior, such as limiting the use of data in the background for a second SIM card to prevent invisible traffic consumption by applications that have been tied to a “non-main” number.

Also worth paying attention to is the roaming settings: If you are abroad, you must manually enable the data roaming option for the SIM card that will be used for the Internet, and without this permission, the phone can block data transmission even if the tariff allows free use in the country.

In some cases, there is a problem when the second SIM card periodically loses the network or switches to Emergency Calls Only mode. This is often solved by manually registering on the network: in the operator's selection settings, you need to turn off automatic mode, wait for the list of available networks to appear, and select your operator manually, after which you can return the automatic selection.

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Optimal configuration for most users: SIM card 1 (main) - calls and Internet 4G/5G, SIM card 2 (additional) - only calls and SMS, 3G/4G network mode.

Frequent problems and ways to solve them

Despite the stability of the MIUI system, users may face typical problems, such as a lack of signal on one of the cards or the inability to make a call. Often the cause lies in incorrectly installed system updates or failures in the operation of the communication module. The first step should always be to restart the device, which resets temporary errors of the radio module.

If the reboot didn't work, try swapping the SIM cards in the tray, which will determine if the problem is with a particular slot (hardware malfunction) or with the SIM card itself. If after the reboot the problem "moved" with the card, then it is the SIM card or the operator, and you need to contact the salon for a replacement.

• 🔄 Reset network settings to factory: Settings → Connection and sharing → Reset Wi-Fi, mobile networks and Bluetooth.
• 📡 Check if the “Airplane” mode is activated for a particular slot in the notification curtain.
• 🔋 Make sure the battery level is sufficient, as at low charge some models artificially limit the operation of the second radio module to save energy.

In rare cases, especially on custom firmware or after unlocking the bootloader, driver conflicts may occur, in which case a complete reflash of the device with the official global version of the software through the computer with data storage or a complete reset helps.