How to turn off one SIM-Map on Xiaomi Redmi: Full Guide

Many users of Xiaomi and Redmi smartphones are faced with the need to temporarily deactivate one of the two installed devices. SIM-This can be caused by the desire to save battery power, eliminate interference with the mobile Internet or simply avoid unnecessary calls outside working hours. MIUI HyperOS provides flexible tools for managing SIM cards, but their location on the menu can vary from version to version.

In this article, we will take a look at all the available ways to manage SIM cards, from standard system settings to hidden engineering menus, learn how to switch modes correctly to avoid losing important contacts or access to the Internet, and discuss the subtleties of working with 4G and 5G networks, which may require a special approach when configuring.

Understanding the workings of your device’s communication module will allow you to optimize your device for your current needs, whether it’s traveling abroad where roaming one card is not desirable, or having to keep only the corporate number active, knowing these features will be a useful skill.

Standard network settings in MIUI and HyperOS

The easiest and most secure way to manage SIM cards is built directly into the operating system interface, so you don't need third-party apps or superuser rights to access the basic functions, but just go to the main settings menu, which is usually represented by the gear icon.

In the list of parameters that you open, you need to find the section that is responsible for wireless connections «SIM-Maps and mobile networks, or simply Mobile Network, is where the main levers of control of the smartphone's communication modules are concentrated.

Once you log in, you'll see a list of all the cards installed, each with its own activity switch, and clicking on the slider instantly disconnects the selected SIM card from the operator's network, making it unavailable for incoming calls and SMS.

• 📱 Open the settings of your device.
• 📡 Go to section. SIM-maps and mobile networks.
• ⚙️ Select the desired SIM card from the list (SIM 1 SIM 2).
• 🚫 Transfer the switch Use to the inactive position.

It is worth noting that once one card is disabled, the system will automatically redirect all data traffic and voice calls to the remaining active SIM card, which is important if you have charging traffic or minutes, as costs can shift to another number.

⚠️ Note: When you disable the main SIM card through which you accessed the Internet, mobile data transmission may be temporarily interrupted until the access point switches to the second card.

The HyperOS shell, which replaces MIUI, has slightly changed the visual design of the menu to make it more minimalist, but the logic has remained the same: each card is managed independently, giving the user complete control over the situation.

Use of flight mode for selective shutdown

Often, there is a situation when you need to quickly turn off all radio modules, but the standard flight mode “jams” both Wi-Fi and Bluetooth, which is not always convenient. In Xiaomi smartphones there is a useful feature that allows you to flexibly adjust the behavior of the flight mode.

You can set up the system so that when you activate the plane, only the mobile network is turned off, and Wi-Fi and Bluetooth remain active, especially in places with poor signal, where the phone is constantly searching for the network and quickly discharges.

To do this, you have to go to the advanced flight mode settings, where you can choose which SIM cards will turn off when you activate this mode, and you can create a fast Wi-Fi-only scenario with a single click.

Settings → Connections and Sharing → Flight Mode → Settings →

In this menu, you'll find checkboxes for each SIM card, and if you tick one of them, you'll tell the system to ignore that card when you go to flight mode, but it's worth remembering that this only works in conjunction with the global flight mode switch in the notification curtain.

• ✈️ Activate flight mode through the notification curtain.
• 🔌 Turn on Wi-Fi and Bluetooth manually if they are turned off.
• 📶 Make sure the network indicators are missing for the selected SIM card.
• 🔋 Enjoy battery life without losing local connections.

This approach is useful at night or in theaters where silence is required, but you need access to instant messengers via Wi-Fi. It is a faster alternative to manually turning off the SIM card through a deep settings menu each time.

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Use shortcuts in the notification curtain to quickly switch network modes so you don’t get into deep menus every time.

Set data priorities and challenges

Sometimes you don't need to completely shut down your SIM card, just redistribute the load between them. MIUI-based Android allows you to flexibly manage which card is responsible for the Internet and which is responsible for voice communication.

The SIM management menu has separate destinations for default card assignments for mobile internet and voice calls, which allows you to keep both cards active, but use only one of them at a particular time.

For example, you can leave a second SIM card active only to receive SMS from the bank, turning off data transfer on it, which will prevent background traffic consumption and battery charge, but will retain the ability to receive confirmation codes.

It is important to properly configure the APN hotspot for the card chosen as the primary for the Internet. If the Internet stopped working after the switch, check the access point settings in the corresponding menu subsection.

Also worth paying attention to is the Smart Switch feature, which allows the phone to automatically use the card with the best signal for calls if the main card is temporarily unavailable, and disabling this feature can help lock the load on a particular module.

Problems with the definition of the second SIM card

Users of dual-sim phones often face a situation where the phone stops seeing one of the SIM cards, this can be a software glitch or a problem with the contacts of the tray. Before carrying the device to the service, it is worth trying software methods of solving.

The first thing you need to do is check if the slot is activated in the settings, sometimes after the system update, the settings are reset, and the second SIM card is software disabled, and turn it on through the menu described in the first section.

If the software switch doesn't help, try removing the tray and wipe the SIM card contacts with a soft dry cloth. Contact oxidation is a common cause of unstable operation, especially in devices that have been in use for more than two years.

• 🔄 Restart the device with installed cards.
• 🧹 Wipe the golden contacts of the SIM card with a lastic or alcohol.
• 📝 Check if the SIM card is trimmed to the desired size (Nano-SIM).
• 🔍 Make sure the tray is inserted before the click and with the correct side.

In rare cases, the problem is that communication standards are incompatible: if one card is very old (2G/3G), and the phone is new and is set to work only in 4G/5G, conflicts can arise, in which case replacing the SIM card from the operator with a new one usually solves the problem.

⚠️ Warning: Don't try to insert a SIM card tray by force.If it doesn't enter easily, you may be inserting it with the wrong side, which can damage the pins inside the slot.

The effect of two SIM cards on the autonomy of the device

Using two active SIM cards significantly increases power consumption, and the smartphone has to constantly communicate with two different base stations, which makes the radio module work in a heightened mode.

The effect is particularly noticeable in areas of insecure reception: if one card constantly loses signal and searches for the network, the battery discharge occurs at an accelerated rate, in such situations, temporarily shutting down the second SIM card can extend the life of the device by 20-30%.

In addition, the background activity of applications tied to the second number also consumes resources, Messengers, banking applications and delivery services can actively use the second card's communication channel for notifications.

To maximize savings in critical situations, you can use 2G Only mode for the second SIM card if you only need it for calls, which will reduce power consumption, since the module will not waste resources on maintaining a high-speed 4G/5G connection.

Engineering menu and hidden settings

For advanced users, there is an option to access the engineering menu where you can fine-tune the radio module parameters, but using these settings requires caution, since incorrect changes can lead to loss of communication.

Entering a special code into the dialer gives you access to equipment testing, and you can see the signal level in dBm, switch your preferred network type, or reset the radio module settings.

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In the Phone Information menu that opens, you can find the "Enable the radio module" switch, which is equivalent to software retrieval of the SIM card, which is a powerful tool if standard disconnection methods do not work due to system errors.

Keep in mind that the codeset may vary depending on the device’s processor (Snapdragon or MediaTek) and Android version. On newer versions of HyperOS, access to some of the engineering menu features may be limited to developers.

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The use of the engineering menu is justified only in case of failure of standard settings or for diagnosing communication problems.