Owners of modern smartphones Xiaomi, Redmi and Poco often face the need to use two carriers at the same time, this can be the separation of personal and work contacts or use different tariffs for the Internet and voice calls. However, when it comes time to make a call, the system may not know which network to use by default, requiring each time to clarify the user.
Competent SIM selection allows you to automate this process, saving time and eliminating unnecessary pressing. The MIUI shell or the new HyperOS provides flexible tools to manage call priorities. Understanding these mechanisms is critical for comfortable operation of the device in two active lines.
In this article, we will discuss in detail how the network selection algorithm works, where hidden settings are located, and how to avoid common mistakes when the phone forgets your SIM card at the most inopportune time.
The principle of network selection system on MIUI and HyperOS
The operating system installed on Xiaomi smartphones uses a complex logic of prioritizing outgoing calls. By default, if the user has not set strict rules, the system offers to choose from the user. SIM-The card before each dial or the one that made the last call can be annoying if you're used to calling from one particular number.
The algorithm is based on the com.android.phone module, which handles connection requests. When a call is received, the system checks user preferences. If there is no explicit rule for the selected contact or number type (mobile, city), the global default setting takes effect. It is important to understand that these settings can be reset after a firmware update or forced reboot of the communication service.
Android and Xiaomi are constantly improving this mechanism by adding smart switching features, for example, if one network lost a signal, the system can automatically redirect the call to the second active line if the option is activated in the operator or device settings.
⚠️ Note: After a major system update (e.g. transition from the MIUI 14 on HyperOS - setting priorities SIM-The cards can be reset to factory values. Be sure to check them immediately after the update.
To understand the process, it is worth mentioning that the choice of card can depend not only on the settings of the phone, but also on the type of number dialed. Some operators require the selection of a specific SIM to correctly display the balance or activate specific services, which creates an additional layer of complexity in managing calls.
Where to find the management settings SIM-map
To get full control of which SIM card to use for calls, you need to go to the appropriate menu section. The path to these settings may vary slightly depending on the shell version, but the general logic remains the same. You need to open the Settings app and find the partition responsible for connecting.
In most current versions MIUI The path is as follows: Settings → SIM-In some cases, this item may be called simply Connect and Share or be inside the Additional menu. This is where all the controls of your device's two physical slots are concentrated.
Once you enter the map management menu, you will see a list of all installed SIM modules. This displays information about the operator, signal level and current status of each card. The interface is divided into logical blocks: settings for each card individually and global default settings for the entire device.
- 📱 Card 1: The main slot that is often used for default voice communication.
- 🌐 Card 2: an additional slot, often used for mobile internet or work calls.
- ⚙️ Default settings: section where priority is given for calls, SMS data transmission.
Note that in the same menu, you can temporarily turn off any of the SIM cards without physically retrieving them, a useful feature if you are in a bad reception zone and want to save battery power by leaving only one number active for important incoming ones.
Why can the settings be hidden?
How to Set the Default SIM Card for All Calls
The easiest way to get rid of persistent system questions is to assign one card to the main card for all outgoing calls, which will cause the phone to automatically use the selected number when dialing any contact from the phone book or manually entering numbers. → SIM-Maps and mobile networks need to find the call or voice.
Click on this, and the system will give you a list of options available. You can choose Always ask if Card 1 or Card 2. Choosing the option with a particular card fixes the rule at the system level. Now, regardless of who you call, the phone will try to connect over the selected network.
However, it is worth considering that setting a hard priority has its nuances: if the selected SIM card is out of range or is blocked, the call simply will not pass, and the system will not automatically suggest switching to a backup option if you do not use special operator functions, so it is important to monitor the status of the main card.
| Selection regime | Description of behaviour | When to use |
|---|---|---|
| Always ask | The phone opens the dialog box before each call. | If you are actively using both SIMs for different purposes |
| Map 1 (Main) | Automatic set through the first slot | If the first SIM is used for 90% of calls |
| Map 2 (Additional) | Automatic dialing through the second slot | If the main SIM is only needed for the Internet |
This change is instantaneous. You don't need to restart the device or restart the Phone app. You can check the result by trying to dial any number -- if the selection window doesn't appear, you've been successful.
Personalized settings for contacts and latest calls
Global setting is convenient, but life often dictates its terms. There are situations where a particular subscriber needs to call strictly from a certain number, regardless of the general rules. Xiaomi has a feature that links a SIM card to a particular contact, which allows you to flexibly manage costs and communication.
To set this up, open the Contacts or Phone app and go to the caller card you want. At the top of the screen, next to the call button or in the optional action menu (three dots), the current SIM card icon can be displayed. By clicking on it, you can choose which card to call that person from by default.
It also remembers your last choice, and if you call your mom from a work SIM, the next time you dial her number, the phone will automatically suggest you use the same card, even if the general settings are different, called "smart memory," and it works in the background, making it easier to re-calm.
- 📞 Contact binding: allows you to fix a card for a specific person forever.
- 🕒 Call history: a call log repeats from the same SIM as the previous one.
- 🔄 Quick switching: at the time of dialing, you can quickly change the card by clicking on the icon SIM.
This approach strikes a balance between automation and control, and you can set a general rule for everyone, but have exceptions for important contacts where the cost of a minute or the quality of communication is critical.
☑️ Checking the contact settings
Quick dial function and hot keys
For those who appreciate speed, Xiaomi smartphones have a quick dial feature that allows you to assign a SIM card to call a contact fixed to the number 2 to 9 in lock mode or on the desktop, which is especially true for emergencies or frequent calls to loved ones.
You can set up through the Phone app. Go to Settings (three dots or a gear) and find Quick Call. Here you will see a list of numbers. You can click on any of them, you can select the contact and, importantly, specify which one to use. SIM-The card should be called when activating this button.
If you assign a quick Husband call to the number 2 using SIM card 1, but in the general settings the priority is changed, the quick call will still go through card 1, as the fast dial rule has a higher priority in this context.
⚠️ Warning: Be careful when setting up a quick call to numbers that you may accidentally click in your pocket (such as a coverless case).This can lead to unintentional calls to the selected number.
In addition, there are third-party widgets and launchers that allow you to bring individual icons for calling from different SIM cards to the same contact, an advanced level of customization available through the installation of additional applications from the GetApps store or Google Play.
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Tip: If you often forget which SIM the call comes from, turn on the icon display SIM-You can do this in the theme or interface settings of the phone.
Solution: Why the phone doesn't choose a SIM card
Sometimes users are faced with a situation where the settings are confused, and the phone no longer remembers the choice of the SIM card or offers to choose it every time, ignoring the established rules, this can be caused by a software failure, an application conflict or an error in the operation of the communication module.
The first step in solving the problem is to clear the cache of the Phone and Contacts application. To do this, go to Settings → Apps → All Apps, find the Phone system application, click Memory and select Clear Cache. Don't confuse it with Clear Data, as this can delete the call history.
If clearing the cache didn't help, try switching network mode.Put the phone to 3G Only or 4G Only, wait a few seconds and return back to Preferably 4G/5G. This action restarts the radio module and often eliminates the temporary network login glitches.
In extreme cases, if the problem is systemic, resetting your network settings may help. Please note that this action will delete your stored Wi-Fi passwords and Bluetooth settings, but will not affect your personal files and contacts.
Settings → Connection and Sharing → Reset Wi-Fi, Mobile Networks and BluetoothAfter this procedure, the phone will restart the network modules, and the SIM card selection settings should return to the correct operation. If the problem persists, it may be a physical malfunction of the SIM card or slot, and it is worth checking their operation on another device.
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Network resets are a radical, but often the only way to fix software selection errors. SIM-cards if simple methods do not help.