Modern smartphones like the Xiaomi Redmi Note 8 Pro are designed to meet the needs of active users, who often have to use multiple numbers at once. However, when you buy a device, many owners are faced with a situation where after physical installation of the communication card, it is not detected or activated automatically. MIUI or.
Most of the time, the problem is solved by simply switching the switchboard to the settings menu, but sometimes more advanced diagnostics are required. The dual SIM card on board allows you to flexibly manage communication costs, separate work and personal contacts, and enjoy advantageous tariffs from different operators. It is important to understand that the proper functioning of communication modules depends not only on the settings, but also on the physical condition of the tray.
This guide describes in detail the process of activating the second slot, setting call priorities and mobile Internet. We will analyze the typical errors encountered by Redmi Note 8 Pro users and offer effective methods for eliminating them without the need to contact a service center.
Physical installation and tray inspection
Before you go to software settings, you need to make sure that the physical installation of the media is correct. The Redmi Note 8 Pro uses a combined tray that allows you to install two Nano-SIM cards or one card and a MicroSD memory card. Installation errors often lead to the fact that the device does not see the second module.
To extract the tray, use a special paper clip included in the delivery, or a thin needle. There is a hole on the bottom end of the smartphone that you need to press until you click. Be careful: remove the tray smoothly so as not to damage the internal contacts. Pay attention to the shape of the cutouts — they correspond to only one correct position of the chip.
⚠️ Warning: Never try to force the tray in. If it doesn't enter smoothly, you've lost orientation.
Once you have the cards installed and the device turned on, the system should automatically recognize the new media. If the operator icons appear on the screen, but the second card is not active, move to software activation. In rare cases, you need to clean the contacts with a stripe if you see oxidation on the metal.
☑️ Installation verification SIM-map
Activate the second SIM via MIUI settings
The main method of enabling the second number is to use the built-in SIM control menu.The MIUI shell installed on the Redmi Note 8 Pro provides a user-friendly interface to control both slots. Often by default, the second slot can be turned off to save power or if a card has not been installed in it before.
To activate the module, go to Settings, then select SIM cards and mobile networks. Here you will see a graphical representation of both slots. If the second slot is displayed in gray or marked "Not active", click on the appropriate switch. The system will request confirmation of action, after which you will register in the operator's network.
You can also set up usage scenarios in the same menu, such as choosing which card to use for outbound calls by default or which channel to use for mobile data, and the flexibility of settings allows you to adapt the phone to any user's needs, whether it's business or personal use.
- 📱 Go to the Settings menu → SIM cards and mobile networks for access to management.
- 🔀 Use the switch Enable opposite the image of the second SIM card.
- 📶 Check the network status: operator name and signal level should appear.
- 📞 Assign a preferred card for voice calls and SMS-message.
Setting Call Priorities and the Internet
After successfully activating both numbers, the user is faced with the question of optimal task allocation. Xiaomi Redmi Note 8 Pro has a convenient tag system that allows you to assign each card a name (for example, "Work", "Home", "Internet") and a color indicator, which helps to instantly determine which channel is through the connection.
In the SIM card settings section, you can set the default card for data transfer. This is critical, because with active mobile Internet on one card, the second can go into standby mode or work on 2G networks if VoLTE is not enabled. For modern tariffs, it is recommended to choose a card with unlimited traffic as the main one for the Internet connection.
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Assign each SIM card a unique color and name in the settings - this will help you instantly understand from which number the call is coming, without looking at the contacts.
Also worth paying attention to the function "Use mobile data of the second SIM for calls." If the main card is busy talking or is in a low coverage zone, the phone can automatically switch data to the second active line, ensuring continuity of connection in messengers and the browser.
Solving Network Definition Problems
Sometimes it happens that a physically healthy card is not determined by the system. First of all, you need to eliminate software failure in the radio module. On the Redmi Note 8 Pro, this is often solved by rebooting the device or switching the network mode. Try temporarily setting the "3G Only" or "4G Only" mode to force the search network.
If simple methods don’t work, check to see if the SIM card itself is blocked by the operator, move the problem card to the first slot or to another phone, and make sure that the device doesn’t have security restrictions or third-party applications blocking access to the network.
| Symptoms. | Possible cause | Method of decision |
|---|---|---|
| No signal (cross) | Network malfunction | Select Preferably 4G |
| Required. PIN-code | Protection of the operator | Enter the code or disable in the settings |
| Wrong IMSI | Damage to contacts | Wipe the chip and move the map. |
| Searching the web is endless | Firmware failure | Resetting network settings |
⚠️ Warning: If the phone writes "No Service" on both cards at the same time, there may be a problem in the antenna module or after the device crashes.
Resetting network settings and software updates
When manual settings fail, the effective method is to reset the network to factory values, which won’t delete your personal files, photos or apps, but will return all network configurations, including Wi-Fi passwords and Bluetooth settings, to their original state.
To perform the reset, go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth. Confirm the action and wait for the interface to restart. Once the phone is turned on, re-enter your carrier’s APN settings (usually they come automatically as SMS) and check the second SIM card.
How to enter APN settings manually?
Don’t forget to update MIUI regularly. Xiaomi engineers are constantly releasing patches that fix modem errors and improve compatibility with carriers. You can check for updates in the About Phone section by clicking on the system version.
Features of working with two operators
The use of two different carriers on the same Redmi Note 8 Pro device has its technical nuances. The main limitation concerns voice technology. If one operator does not support VoLTE (Voice over LTE), then during a conversation on this card, the second card may temporarily lose communication or switch to 2G mode, making it impossible to receive a call to the second number simultaneously.
To minimize problems, it is recommended to activate VoLTE for both numbers, if your region and operator support this function, and turn on in the SIM card settings menu: you need to activate the "Use VoLTE" switch, which will allow you to conduct high-quality conversations over a 4G network and simultaneously use fast Internet.
- 📡 VoLTE technology allows you to speak and use 4G simultaneously.
- 📉 Without VoLTE, when calling, the phone can switch to 2G/3G.
- 🔄 When calling the first SIM card, the second one may not be available.
- ⚙️ Check your carrier’s VoLTE support before setting up.
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For the two lines to work smoothly, it is critical that both operators support VoLTE in your area, otherwise calls to the second line may be missed during a call.