Buying a new smartphone or replacing a carrier often puts users in the first place with a communication module setup. Owners of Xiaomi, Redmi and Poco devices may find themselves in a situation where, after installing a plastic carrier, the phone does not see the network or requires additional steps to register with the operator’s network.
Activation process SIM-cards on the devices of the Chinese brand has its own nuances, different from standard Android smartphones. MIUI or HyperOS has a specific management menu for two SIM cards that can confuse an inexperienced user, and understanding the logic of the communication module will avoid unnecessary trips to the service center and quickly establish communication.
In this guide, we will cover all the steps from the physical installation of the chip to the complex cases where you need to manually configure access points or reset network settings, you will learn how to correctly allocate roles between cards and what to do if the device writes “Emergency Calls Only”.
Physical installation and primary diagnosis
The first step is always to properly fit the card into the tray.Modern Xiaomi smartphones use a combined slot or a separate triple tray, which requires careful extraction.Use a special clip included in the kit, or a thin needle to press the hole next to the device's frame.
It is important to make sure that the chip's golden pins are pointing down (or up, depending on the tray model) and the cutout shape is completely the same as the pattern in the tray.Incorrect installation can cause the phone to not see the card at all.
⚠️ Warning: Never insert a SIM card when your phone is on unless the device supports Hot-swap. Although current models allow you to change cards on the go, it is safer to reboot after installation to initial activate and recognize new network settings.
After you turn on the device, look at the top status bar. If you see the icons with the signal, but there is no operator name, you may need to enter PIN-If you see a crossed-out SIM card, check the density of the contacts. Sometimes oxidation or dust in the tray interferes with contact.
☑️ Check of the physical installation
Basic configuration via MIUI and HyperOS menu
If the map is physically set correctly, but there is no connection, you need to refer to the software settings. MIUI It offers flexible management of two SIM cards, allowing you to prioritize calls and mobile internet separately. → SIM-maps and mobile networks.
Here you will see a list of installed cards. Click on the SIM card to open the extended menu. Make sure the "Enable" switch is active. In the same section, you can specify the network type (preferably 5G/4G/LTE) and select the operator manually if the automatic search does not give results.
Special attention should be paid to roaming settings if you are abroad or use virtual operators. activation of data may require the inclusion of the option "Roaming data" even in the country for some users. MVNO-operator.
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Use the function "Help in the selection" SIM-"cards" in settings, if your phone is constantly switching between cards when you call.
Remember that for VoLTE and VoWiFi (wi-fi calls) to work, these features must not only be enabled in your phone settings, but also supported by your carrier. The SIM card settings menu often has separate switches for these technologies.
Solving Network and IMEI Definition Problems
One of the common problems with Chinese smartphone owners (China ROM) is the lack of communication in European or Russian networks, due to differences in frequency and software restrictions. If the status says "No" or "Emergency Calls Only", the first thing to do is check for IMEI.
On the phone keyboard, type *#06#. IMEI zeros or dashing are displayed, so the modem calibration has flown or NVRAM-This is a serious software bug that requires flashing or restoring through the engineering menu.
| Symptoms. | Possible cause | Decision |
|---|---|---|
| No IMEI (zero) | NVRAM crash, Chinese firmware | Global version firmware, IMEI restoration |
| "Emergency only" | Wrong type of network, blocking | Change of network type to 3G/2G, check of locks |
| Continuous search | Bad contact, antenna damage | Cleaning the tray, checking the antenna plume |
| No SMS activation. | Overflowing memory, blocking spam | Cleaning up SMS, checking the blacklist |
If IMEI is in place but the network is not catching, try resetting your network settings. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth.This action will delete stored Wi-Fi passwords, but often solves problems with registering on the cellular operator's network.
What if IMEI is zero?
Configuring APN access points for mobile Internet
Even if the SIM card is active and calls pass, mobile Internet may not work due to incorrect APN settings. Usually Xiaomi automatically tightens the settings from the operator, but in the case of new virtual operators or corporate tariffs, manual settings are required.
To change the parameters, go on the Settings path → SIM-maps and mobile networks → (Choose a map) → Access points (APN). Press the "New Access Point" button or"+" In the upper right corner, you need to enter the data provided by the operator: name, APN, login and password (if required).
⚠️ Note: When creating a new access point, don't change the protocol type unless you're sure of the operator's requirements. IPv4/IPv6, What's the best choice? One letter error in the field. APN (For example, the Internet instead of mts will lead to the lack of Internet access.
Once you have entered all the options, be sure to click the menu (three dots) and select Save, and then activate the created point by placing a marker next to it. Without saving, the changes will not take effect, and the phone will continue to use the old non-working options.
Activation of eSIM on Xiaomi smartphones
Xiaomi’s current flagships support eSIM technology, which allows you to activate a number without a physical plastic card.This is convenient for travelers and those who want to use two SIM cards in models with one physical slot. QR-code from your carrier.
To add a profile, go to Settings → SIM-maps and mobile networks → Add the eSIM tariff.The camera will open for scanning QR-Make sure the device is connected to a stable Wi-Fi network, as the profile is downloaded from the Internet.
Once the scan is successful, the phone will upload the operator profile, which you can name (e.g., "Work" or "Travel") and prioritize use. It is important to note that multiple eSIM profiles can be stored on a single device, but usually only one is active at a time (plus a physical SIM card, if the design permits).
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eSIM is not tied to a particular slot, it is software-based, and you can easily switch between different operators in settings without changing your plastic cards.
Frequent errors and ways to fix them
Users often encounter a message"SIM-Card blocked after multiple incorrect entry attempts PIN-In this case, the phone will ask for PUK-You can find it on the plastic card holder that came with the SIM card, or in the operator's personal office. PUK-code more than 10 times will lead to the final lock of the SIM card, and it will have to change.
Another common problem is the conflict of modes of operation, if you switch your phone to "On the plane" and forget to turn off, the network will not work, and also check whether the "Do Not Disturb" mode or blocking incoming calls, which can create the illusion of a broken SIM card, is turned on.
In rare cases, the problem lies in the operator’s chip itself: if the SIM card is very old (released more than 5-7 years ago), it may not work correctly in modern 4G/5G networks. In this case, the best solution would be a free replacement of the SIM card in the operator’s cabin with a number saved.