Modern Xiaomi smartphones running MIUI or HyperOS shells provide users with extensive network connectivity management capabilities. Often, there is a situation when you need to temporarily suspend one of the SIM cards, for example, to save battery power or to avoid incoming calls during working hours. Software shutting down the communication module is more flexible and safer than physically removing the plastic media from the tray.
Owners of Redmi and Poco devices may face the need to switch between slots or completely block access to the cellular network without losing data.The system allows you to manage each slot independently, which is especially true for models with support for two active SIM cards at the same time. In this article, we will discuss in detail all available ways to deactivate the SIM card, from the standard settings of the system to deeper locking methods.
Understanding how to properly manage network interfaces will help you not only control communication costs, but also increase the level of digital security of your gadget. SIM-the card does not delete the contact or SMS-Messages stored on a chip, making this process completely reversible. Next, we'll look at step-by-step action algorithms for different use cases.
Software Disconnection through Network Settings
The easiest and most common way to temporarily remove your phone from the network is to use the built-in SIM card management menu, which requires you to open the main settings menu of your device, and the gear icon is usually located on your desktop or in the notification curtain. Find a section that, depending on the firmware version, may be called SIM cards and mobile networks or SIM-maps and mobile networks.
In the menu that opens, you'll see a list of all the communication modules installed in the phone. Xiaomi's system allows you to manage each of them separately. If you have two cards inserted, they will be labeled SIM 1 and SIM 2, often with the ability to assign them labels, such as "Main" or "Working." To deactivate one of them, just click on the appropriate switch next to the operator's name.
Once the slider is switched to off or off, the network icon at the top status bar will disappear for the selected slot. The phone will no longer register with the operator's network, and incoming calls to that number will be unavailable, and the subscriber will hear a standard message that the subscriber is unavailable. This action does not require the device to restart and takes effect instantly.
⚠️ Note: When the software disables the SIM card, you will not be able to accept SMS-confirmation codes from banks or messengers to this number until re-activation.
Importantly, when you use two SIM cards, you can flexibly adjust which one is used for data and which is only for voice calls. If you turn off the SIM card assigned by the main channel for the Internet, the system will automatically switch to a second active card or Wi-Fi, if available, this flexibility makes it very convenient to manage tariffs on Xiaomi.
Using flight mode to block communications
An alternative method that allows you to turn off all radios at once is to activate flight mode, which is suitable in situations where you need fast all types of communication, including Bluetooth and Wi-Fi (although the latter two can be turned back on manually).
When you activate flight mode, the phone forcibly breaks the connection to all cell towers. Unlike selectively disabling the SIM card, this method blocks both slots at the same time, which can be useful in a movie theater, an airplane, or in situations where maximum concentration is required and no distractions are involved.
The unique feature of this MIUI shell mode is that it's fine-tuning. Once you've turned on the flight mode, you can separately activate Wi-Fi or Bluetooth, leaving the cellular network off. However, if your goal is to turn off only one particular SIM card and the second one should continue to work, this method is not suitable, since it works globally on all network interfaces.
There is also a nuance associated with the alarm clock: on many Xiaomi and Redmi models, the alarm clock continues to work even in flight mode, which makes this method safe to use at night if you are afraid of missing the morning rise, but want to sleep without calling. However, if it is critical that you can access one of the SIM cards in an emergency, it is better to use the selective shutdown described in the previous section.
Lockdown SIM-map PIN-code
A more radical and secure way to protect your SIM card is to install it. PIN-Unlike a simple software shutdown, this method requires you to enter a code every time you try to activate a slot or reboot your phone. If the code is not entered, the SIM card remains locked and invisible to the network, which provides a high level of data protection when you lose your device.
To configure this function, go to the Privacy Protection or Security menu, then find System Security and select Settings. SIM-Here you will find the option "Blocking" SIM-When activated, the system will require you to enter a standard code (usually 0000 or 1234 if you have not changed it before), and then prompt you to set your own 4-digit password.
After installation PIN-And even if you just reboot the phone or you just retrieve and insert the SIM card back, it won't work without entering the password. It creates an additional barrier for intruders. PIN-If you use your SIM card to make calls or access an Internet bank, it will be impossible to use it.
☑️ Security check SIM
⚠️ Note: Be extremely careful when entering PIN-Three wrong attempts will result in the SIM card being blocked, and it will take a lot of time to unlock it. PUK-code that is on a plastic card-holder issued by the operator.
It's worth distinguishing. PIN-code to unlock the phone screen and PIN-SIM card code. These are two different layers of protection. The screen protects access to the Android interface and applications. PIN The SIM card protects the SIM itself as a network ID, even if an attacker pulls your SIM card and inserts it into another phone, without the need to PIN-code it won't work.
Managing your preferred slot for calls and the internet
Often users want to shift the load between them rather than disabling the SIM card. Xiaomi smartphone owners can flexibly adjust which SIM card will be used by default for different types of traffic, allowing them to effectively manage their balance using one card for cheap minutes and another for unlimited internet.
SIM cards and mobile networks have Calls and Mobile Internet sections, and by choosing Calls, you can either prioritize the SIM card or leave the Always Ask option, which is convenient because each time you dial, the phone will ask you to choose which SIM card to call from, which effectively disables automatic selection, giving you full control.
For the mobile Internet, the situation is similar: you can assign one of the SIM cards to the main data transfer card, switching the main card for the Internet is almost instantaneous and does not require a reboot.
| Parameter | Description of function | Impact on the battery |
|---|---|---|
| 4G mode is preferably | Forced use of fourth generation networks | High-end spending |
| Only 2G/3G | Working with old communication standards to save energy | Low expenditure |
| Data roaming | Allow data transfers outside the home network | Depends on the use |
| Wi-Fi calls | Using Wi-Fi Networks for Voice Calls (VoWiFi) | Average expenditure |
Also in this section, you can have network-type settings. If you're in a low 4G area, the phone can constantly look for a signal that quickly lands the battery. In such cases, it makes sense to temporarily switch the network type to 3G preferably or even 2G. This will not turn off the SIM card, but will change the mode of its operation, which can be useful for saving charge in a critical situation.
Physical extraction SIM-map
The oldest and most reliable way to disable a SIM card is to physically remove it from the device. On Xiaomi smartphones, the SIM card tray is usually located on the bottom or top of the case. Removal will require a special clip that comes with the kit, or a thin needle.
The process is simple: press a paper clip into the tray hole, push it a little, and the tray will exit. Remove the plastic card of the correct operator. This method guarantees 100% shutdown, as physical contact with the phone is interrupted. No software glitches or viruses can activate the missing SIM card.
What happens if you remove the SIM card without turning off the phone?
The disadvantage of this method is the inconvenience: if you need to switch between cards often or temporarily turn off one of them, constant manipulation of the paper clip and tray can lead to mechanical wear of the slot. In addition, in models with a combined slot (SIM + microSD), removing the SIM card will require interruption of the memory card if it is installed in the second slot.
Physical extraction is also the only way to save the situation if the phone freezes due to a SIM card error and does not respond to commands, in which case the card can warm or cause modem malfunctions, and only removing it will help bring the device back to life.
Solution and additional settings
Xiaomi users sometimes face a situation where after disabling the SIM card, the network icon does not disappear, or the phone continues to show “No service” instead of completely shutting down. Often this is solved by simply restarting the device. It is also worth checking whether VoLTE or VoWiFi functionality is enabled, which may try to maintain a connection through alternative channels.
In some cases, especially after a firmware update, network settings may get lost. It is recommended to reset the mobile network settings to factory values. This can be done in the SIM card and mobile network menu -> Additional settings -> Reset mobile network settings. This action will not delete your personal data, but will return all network settings to the original state.
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If the SIM card is not detected after switching on, wipe its contacts with a soft eraser or an alcohol wipe. Contact oxidation is a common cause of unstable network operation.
Another important setting is to limit background activity for applications that use a SIM card. If you have disabled the SIM card, but traffic consumption or battery power remains high, check if some applications are using cached data or trying to constantly reconnect. In the Battery menu, you can see the statistics of the consumption of applications.
⚠️ Note: It is not recommended to switch network modes often (2G/3G/4G) It can be placed in a developer menu or an engineering menu without needing it, and it can cause the modem to run in a way that's unstable and the signal to be lost.
For advanced users, there is the possibility of managing SIM cards through ADB-commands, but for the average user, it's redundant. MIUI It's enough to solve 99 percent of the SIM card management problems, and the key is to understand the difference between software shutdown, code locking, and physical extraction.
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The optimal way to disconnect depends on the purpose: for silence – flight mode, for economy – disabling one card, for security — PIN-code.