Changing a mobile operator or losing a card are standard situations that require physical intervention in a device. Owners of Xiaomi, Redmi and POCO smartphones often face the need to remove the tray to install a new chip. Despite the simplicity of the procedure, there are nuances that can lead to slot damage or errors in the communication module.
Modern gadgets are equipped with combined slots, where the memory card can take up space for the second SIM, it is important to understand the architecture of your tray before you start manipulating. Installation can cause the device to stop seeing the network or not turn on at all. We will consider the full cycle of actions, from preparing tools to configuring the network in the MIUI system.
In this guide, we will not only discuss mechanical replacement, but also software aspects. Often the problem lies not in physical contact, but in the settings of APN or blocking IMEI. Following the steps below, you can solve 99% of problems with connecting to the cellular network without visiting the service center.
Tools and workplace preparation required
Before you start, make sure you have everything you need on hand. The main tool is a special paper clip to remove the tray, which comes with the box. If the original key is lost, you can use a thin needle or straightened stationery clip, but you need to act extremely carefully so as not to scratch the case.
Choose a well-lit area with a flat surface. small details such as the tray itself or a new one SIM-It is also recommended to turn off the smartphone before removing the tray, although most modern Xiaomi models support hot replacement.Switching off the power ensures that the system correctly rewrites the network configuration when turned on.
Prepare a new Nano-SIM card. This is the smallest standard used in all current models. If your card is larger, you need to gently break it down along the circuit or contact the communications salon for replacement.
⚠️ Warning: Never use blunted objects or knives to retrieve the tray.You risk damaging the extraction sensor or breaking the latch mechanism, which will require disassembling the entire device.
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If the tray is tight, do not use excessive force. Try to slightly press the paper clip and at the same time sway it from side to side to unlock the mechanism.
Make sure your hands are dry and clean. Fat spots on the card contacts can disrupt signal transmission. Wipe the golden chip with a soft cloth without pile before placing it in the slot.
Algorithm of tray extraction and map installation
The replacement process depends on the specific model of your device. Most budget and mid-range models, such as the Redmi Note or POCO M, use a combined slot. The flagship Xiaomi Mi and Xiaomi 11/12/13/14 series often have a separate memory card slot or are completely devoid of it, providing two full-fledged SIM card spaces.
Find a tray extraction hole. It's usually located on the bottom end of the smartphone next to the USB-C charging port, but in some compact models it can be on the top edge. Insert the tool perpendicular to the body and press before you click. The tray should extend a few millimeters, after which it can be removed with your fingers.
☑️ Procedure for replacement
Look at the extracted item. If you have a combined slot, look at the diagonal markup. One cell has a SIM card installed, the other one has a microSD card installed. You can't physically confuse them because of the different cutout shapes, but it's important not to confuse the SIM 1 and SIM 2 cells if you want to keep the Internet priority on a particular number.
Place the card in a recess so that the bevelled angle matches the tray shape. Contacts should look down to the device board. Carefully move the tray back into the case. It should enter smoothly, without creaking or resistance. If you need force, the map is installed incorrectly or the tray is skewed.
Set up network and priorities in MIUI
Once the smartphone is turned on, the system will automatically identify a new operator. If this does not happen, or if you use two SIM cards, you need to check the settings. → SIM-Maps and mobile networks. Both slots are displayed here, even if one of them is empty.
This section can assign which card will be used for default voice calls and which for mobile Internet, which is critical for rates with different traffic volumes, and it also has a VoLTE switch that allows high-quality calls over a 4G network.
| Parameter | Description | Recommendation |
|---|---|---|
| Mobile Internet | Selecting an Active SIM for Data Transfer | Card with unlimited tariff |
| Default calls | Basic number for outgoing | Personal or work number |
| SMS default | Sending messages from the selected number | A number tied to banks |
| Use 4G. | Forced LTE mode | Included for both cards |
If the automatic APNs don't work, you can manually prescribe them, and usually just click "Restore Default Settings" in the access point menu, and manual creation is rarely required, only for specific corporate rates or roaming operators.
⚠️ Warning: When setting up two SIM cards, make sure both are activated.Sometimes after a replacement, the system may programmatically disable the second slot.
Common Errors and How to Resolve Them
The situation when the phone says "No" SIM-cards" or "Valid SIM", You can see it all the time. First thing you do is check the cleanliness of your contacts. You wipe your chip with an alcohol wipe or a wipe. Oxidation or dust is a common cause of contact loss, especially if you've been using it for a long time.
The second step is to check the card itself, put it in another phone, if it doesn't work there, there's a problem with plastic or locking on the part of the operator, and if the card works on another device but doesn't work on Xiaomi, it could be a frequency incompatibility or a software failure.
Try resetting your network settings. Go to Settings → Connection & Sharing → Reset Wi-Fi, mobile networks and Bluetooth. This action will not delete your personal data, but will return network settings to factory values, which often resolves the problem after a change of operator.
What to do if the tray is stuck?
Rarely, a modem flash or a complete reset is required, but radical measures should be taken to check for MIUI updates, as security patches often fix bugs with network modules from different regions.
Features of working with eSIM on Xiaomi smartphones
Modern flagships of the brand increasingly support eSIM technology, a built-in SIM card. This allows you to activate the tariff without physical contact with the tray. → SIM-maps and mobile networks and see if there is an option "Add the eSIM tariff".
The activation process takes place by scanning QR-It's convenient for travelers to add local tariffs from different countries without replacing physical chips. However, the eSIM is tied to a particular device, and it's not easy to move it to another phone with a simple shift.
It is important to note that some regions, such as China, have versions of phones that do not support eSIM, even if the global version of this model is equipped with it.
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Physical replacement SIM-The card is required only if the chip is damaged or the operator is changed, which does not support eSIM.
If you switch to eSIM, you can dispose of your old plastic card, and make sure you keep all the important contacts before you do so if they were stored on a SIM card, not a Google or Mi Account cloud account.