Xiaomi’s modern smartphones, including the popular Redmi and POCO series, have become an integral part of everyday life, providing constant communication with the world. However, even the most reliable device requires periodic maintenance, and one of the most common procedures is to replace a sim card. This can be necessary when switching to a tariff with a large amount of traffic, when buying a new memory card or in the event of a failure of an old chip carrier.
The replacement process seems rudimentary, but device owners often encounter nuances that are not obvious at first glance: Installation incorrectly can cause the phone to stop seeing the network, or worse, damage the tray contacts. In this article, we will discuss how to change safely. SIM-map, what types of trays exist and how to configure network settings after a physical module replacement.
It's important to understand that the design of the slot can vary depending on the model of your gadget, where you use a combined slot, and somewhere you use separate sockets. In models with IP68 moisture protection, the tray is often tighter, requiring careful but confident effort in extraction. Let's start with the necessary tools and assess the situation.
Preparation for replacement and necessary tools
Before you start mechanical intervention in the design of the smartphone, you need to make sure that you have the right tools. Standard equipment most Xiaomi devices include a special key to remove the tray, but it is easily lost. If you do not have a branded tool at hand, it can be replaced with a thin paper clip, needle or even a earring with a thin rod.
It is critical not to use thick objects such as toothpicks (they break inside the hole) or stationery knives that can damage the spring mechanism, and it is recommended to completely turn off the smartphone before the procedure to avoid short circuits or software errors when determining a new communication module.
Make sure your new one is SIM-The card is the right format. Modern devices use the Nano-SIM standard, which is the smallest, and if you have a larger card, you'll have to cut it off in a special form or replace it with a carrier, which is now done free of charge in most salons.
☑️ Preparedness for procedure
Definition of the tray type and its location
The location of the SIM card slot in Xiaomi and Redmi smartphones can vary. Most modern models use a tray located on the bottom or upper end of the case. However, some budget or older models have found a design with a removable back cover, where the battery and slots are under it.
There are two main types of trays that you can come across:
- 📱 Combined slot: Designed to install one SIM-card and one microSD card or two microSD cards SIM-It's impossible to use three elements at the same time.
- 📱 Triple slot (rare): Allows you to set two SIM-cards and memory cards are independent of each other, but occur mainly in old or specific models.
So if you look at the end of the device carefully, you'll see a small circular hole next to the elongated tray, and that's where you put the tool in, don't confuse the sim tray hole with the microphone hole, which is often located next to the microphone hole, and the instrument enters with a characteristic deaf sound and has no spring mechanism.
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If you are not sure where the microphone is, shine a flashlight into the hole: the microphone hole is usually deeper and the mesh is visible inside, and the spring mechanism is visible in the sim tray.
Step-by-step instructions for removing the tray
The extraction process requires precision, but not excessive force. Take a paper clip or key and insert it perpendicularly into the hole. You should feel a slight click of the spring, after which the tray will slightly extend out of the case.
If the tray doesn't come out, don't push harder -- you may have miscalculated the angle of the tool. Try changing the angle a little bit, keeping the pressure strictly inside the body. Once the edge of the tray appears, gently pull it out with your fingers. Don't pull sharply so as not to damage the contacts.
⚠️ Warning: Never try to remove the tray while the smartphone is on and there is an active data writing process, although in modern models Hot-Swap is supported, the risk of a software error when extracting "hot" still exists.
Once removed, inspect the tray. It usually has a notch indicating the correct orientation of the card. In combined slots, one side is for Nano-SIM and the other is for microSD. It's easy to confuse them, so pay attention to the shape of the notch in the corner of the card.
Proper installation of new SIM-map
Putting a new map is the most important thing. Put the tray on a flat surface. SIM-And you can match the bevelled corner of the card with the appropriate angle in the tray. If you insert the card incorrectly, it just won't fall into the notch until the end -- don't push it!
Some Redmi models use a "sandwich" mechanism, where the card is inserted under spring contacts, while others use a card on top and the contacts are pressed by the tray lid. In side tray devices, the card is usually placed in a recess, and when the tray is inserted into the phone, the contacts are pressed against the board.
What do I do if the card is hanging?
Once the map has taken its place, insert the tray back into the phone's body. Make sure it enters smoothly. If you feel resistance, don't push, take it out and check for orientation. The tray should snap level with the body.
Comparison of characteristics SIM-card operators
When choosing a new operator or tariff, it is important to consider not only the price, but also the technical characteristics of the cards provided. Different operators can use chips of different generations, which affects the speed of registration in the network and the support of modern communication standards.
| Parameter | Standard SIM | USIM (4G/5G) | eSIM (Virtual) |
|---|---|---|---|
| Security | Basic | Tall. | Maximum |
| Network speed | Up to 3G/4G | 4G/5G | 4G/5G |
| Physical wear and tear | Possible. | Possible. | Absent. |
| Replacement of the device | Move the map. | Move the map. | Reprofiling |
As you can see from the table, switching to modern USIM cards or using eSIM technology (if your Xiaomi model supports this feature) offers speed and security advantages, but physical card replacement remains the easiest way to change operators.
Network settings after card replacement
Once the smartphone is turned on, the system will automatically try to identify a new operator. 1-2 If you see the screen saying, "No." SIM-"Calls only" or "Emergency Calls" check the correct installation.
To manually adjust the parameters of the Internet and MMS You have to go to the settings menu. The path is usually: → SIM-maps and mobile networks → Choose a map. → Access points (APN). Here you can create a new access point or reset existing to factory values, which often solves problems with the Internet.
In the Preferred Network Type menu, make sure you select 4G/5G (LTE) mode if your tariff and carrier coverage support this. Sometimes after you change the card, the phone may get stuck in 2G/3G mode, and switching to a faster standard requires manual intervention.
⚠️ Note: If you have changed the operator, but have kept the old number (MNP), activation of the card can take up to several hours or even days, at which time the old card no longer works and the new one has not yet been activated.
Solution and diagnosis
Sometimes, when you change the card, you have problems, like the phone can't see the network, constantly looking for a signal, or it doesn't miss calls. First, try rebooting the device. If that doesn't work, remove the tray and wipe the contacts. SIM-cards with soft dry cloth or eraser (very carefully).
Check if it's blocked. SIM-map PIN-When you turn on, the phone can request a code. PUK, If you have entered three times incorrectly PIN. Code. PUK It's on the plastic base card that was issued in the cabin. PUK 10 times will result in a full card lock.
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If it's new SIM-The card is not detected in any slot, try inserting it into another phone, and if there is no reaction, the card is defective or damaged, you need to replace it with the operator.
In rare cases, the problem lies in the software failure of the firmware MIUI or HyperOS. Reset network settings (Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth) can help restore the correct operation of the communication module without losing personal data.