Xiaomi smartphones have long been popular for their excellent value for money, and the Redmi 4 model has become a real hit of its time. However, many users, especially those who move from button phones or other brands, often wonder about the correct installation of the communication module. Incorrect installation can lead to the fact that the device will not see the network or damage contacts, so it is important to understand the nuances of the design of the tray of this model.
In this article, we will discuss the entire process, from finding a paper clip to setting up a network in the MIUI system. You will learn how slots differ, how to determine the orientation of the chip and what to do if the smartphone stopped seeing the operator after changing the card.
Before you start physically affecting the body of the device, you need to prepare the workplace, and you need a clean, dry surface with good lighting, so you don't lose small parts. Also make sure your hands are dry and clean, as fat or moisture can negatively affect your contacts. SIM-card or phone.
Tool preparation and completeness check
To extract the tray, you'll need a special key that usually comes with the device. If the original paper clip is lost, you can replace it with a regular paper clip, straightening one of the ends, or a thin needle, and the main thing is to use an object with a diameter suitable for the hole so that the pusher mechanism inside the case does not damage.
Make sure you have yourself on hand. SIM-The Xiaomi Redmi 4 uses the Nano-SIM standard, which is the most common to date. If your card is larger (Micro or Mini), it should be carefully trimmed along the contour or, more safely, replaced with a new one by the operator, keeping the number.
It is also important to check the status of the card itself for visible damage, chipping or oxidation of contacts. Dirt on golden contacts can cause an unstable signal. If you notice contamination, they can be gently wiped with a soft dry cloth, but in no case do not use wet wipes or alcohol immediately before installation.
⚠️ Warning: Never force a tray into the body unless it enters freely, which can cause internal rails to break or damage to the motherboard.
Slot location and tray extraction
In the Redmi 4, the SIM card tray is located on the top end of the device, a classic location for smartphones of the period that provides convenient access without having to remove the back cover, as was the case in older models with non-removable batteries, the slot is a narrow slot, next to which there is a small circular hole.
To extract the tray, take a prepared key or paper clip and insert it into the hole perpendicular to the phone's body. Press smoothly but confidently until you feel a slight click and the mechanism pushes the tray out. After that, gently pull the tray with your fingers until fully removed.
The design of the tray in Xiaomi Redmi 4 combined: it provides space for one Nano-SIM and a separate hybrid slot that can work with either a second Nano-SIM or a microSD memory card. It is important not to confuse orientation when re-installing, as the shape of the chip cutout is unique for each size.
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Use a smartphone flashlight or lamp when removing the tray if the room has poor lighting so as not to scratch the phone body with the sharp end of the clip.
Orientation and installation SIM-map
The most important thing is to get the map in the tray right. The tray itself often has a schematic image that tells you how the chip should be positioned. In Redmi 4, the map is set by the contacts down, and the cut angle must match the corresponding ledge in the tray's pad.
If you install two SIM cards, look at slot numbering. Usually the first slot (SIM 1) is for the main carrier card that the mobile Internet is configured on, and the second (SIM 2) is for additional calls. While modern versions of MIUI allow you to flexibly set priorities, the physical location can affect the speed of the initial network determination.
When you put the card in the tray, make sure it lies flat and does not protrude beyond the edges of the metal frame. If the card protrudes, when the tray is closed, it can damage or damage the contacts inside the phone. The map should lie level with the edges of the tray, securely fixed in its seats.
☑️ Pre-installing check
Inserting the tray back into the smartphone
Once the cards are in place, you need to carefully insert the tray back into the case, and here it is important to keep the plane right: the tray should enter the groove easily, without distortion. If you feel resistance, do not press, but take out the tray and try to turn it over or change the angle of inclination.
The Xiaomi Redmi 4 uses a locking mechanism that snaps when fully immersed. Stick the tray to the end until its outer bezels match the phone's body. The characteristic click in this model may not be heard due to the tight fit, so focus on visual alignment levels.
Once you have the tray installed, turn on the device. If the phone was turned on during the manipulation, the system may not see the changes immediately. In this case, you will need to restart. Usually, Android automatically detects the presence of a new one. SIM-maps and offers to configure network parameters.
⚠️ Warning: Make sure you insert the tray with the correct side. Trying to insert it "upside down" can short the contacts and the device fails.
Network and settings in MIUI
After successful installation and activation of the phone go to the settings menu. You are interested in the Settings section → SIM-This is where the basic configuration of the communication modules is made, and in this menu you'll see the list of installed cards and their status.
For each SIM card, you can specify a name (e.g., "Work", "Home") and select the operator's logo, which makes navigation easier. More important is choosing the default card for voice calls and for mobile Internet. In Redmi 4, these settings are spaced, allowing, for example, to call through one operator, and the Internet to spend from the tariff of another.
Network Type is also available in this section. For maximum comfort, choose Preferably 4G or 4G/3G/2G (auto) mode, which will automatically switch to the fastest available communication standard in your coverage area.
Solution: If the SIM is not defined
Sometimes it happens that after installation the phone says "No". SIM-"Put in the cards" or "Put in" SIM-First, check if the tray is sitting tight. Sometimes it's enough to press it slightly or extract it and re-insert it so that the contact is restored. Contact oxidation is a common problem with old cards.
If mechanical repositioning doesn't work, try checking the map on another device, which will let you know if the problem is in the SIM itself or in your smartphone, and it's also worth trying to clean the contacts with a stripe (very carefully) or alcohol if you see oxide film on them.
In the software part, resetting your network settings can help. Go to Settings → Advanced Settings → Recover and Reset → Reset your Wi-Fi, mobile Internet and Bluetooth settings. This action will not delete your personal data, but will return network settings to factory values, which often solves the problem of incorrect registration on the network.
What to do if a contact on the phone is burned?
Comparison of slots and support of technology
It is important for users to understand the difference between the slot capabilities in Redmi 4. Although both slots support 4G, the simultaneous operation of two cards in LTE mode can be limited software or hardware depending on the regional version of the firmware.
Below is a table that will help you quickly navigate the characteristics of slots for this model:
| Characteristics | SIM 1 slot | SIM 2 slot / microSD |
|---|---|---|
| Map format | Nano-SIM | Nano-SIM or microSD |
| Support for 4G LTE support | Yes (main) | Yes (secondary) |
| Hot replacement. | No (removal required) | No (removal required) |
| Max, memory capacity. | N/D | Up to 128GB (microSD) |
It’s worth noting that using a memory card in a hybrid slot makes it impossible to install a second SIM card. You have to choose which is more important to you: an additional number or an extension of the internal memory of the device. In an environment where internal memory of 16 or 32 GB may be lacking, this choice becomes critical.
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The hybrid slot in Redmi 4 allows you to choose between a second SIM card and a memory card, but you can not use both options at the same time.
Safety and care of the connector
Jack for SIM-maps are a vulnerability for any smartphone, where dust, pile and moisture can get into. To prolong the life of the device, try not to hold the phone tray up in dusty places. Regular but careful cleaning of the tray from dust will help avoid contact problems.
If the phone is in the rain or in high humidity, don't rush to put the tray back in right away. Let the device and the tray dry at room temperature. The moisture inside the slot can cause contacts to corrosion or short circuit when power is applied.
When SIM cards are frequently replaced (e.g. when traveling), it is recommended to use an adapter or holder to store the retrieved cards so as not to lose them or damage them.Storing the card "on weight" or in your pocket along with the keys can lead to scratches on the contact area.
⚠️ Warning: Avoid using metal objects to clean contacts inside your phone.The metal can leave microscopic scratches or close contacts, leading to irreversible consequences.
Additional opportunities to work with two cards
With Xiaomi Redmi 4, you get access to the convenient features of the MIUI shell to manage two numbers. For example, Standby mode allows you to completely turn off one of the SIM cards software without physically removing it, which is useful when you need to save battery power or avoid unnecessary calls.
You can also set limits for outbound calls, so that certain contacts are always called from a specific number (for example, personal calls from a personal SIM, and workers from a corporate one), which is set up in the phone book or in general call settings.
For users who change operators frequently, quick switching is useful, and in the notification curtain (control panel) you can display widgets to quickly turn on and off SIM cards or switch mobile Internet between them with a single touch.
How to extend the life of the battery with two SIM cards?
Conclusion
The process of installing a sim card in Xiaomi Redmi 4 is quite simple, if you follow the accuracy and sequence of actions. The correct orientation of the chip, the purity of contacts and attentiveness when working with the tray ensure stable communication. Don’t be afraid to experiment with network settings to find the optimal balance between speed and power consumption.
Remember, the hybrid slot in this model requires the user to decide whether to prioritize a second SIM card or additional memory. Weigh your needs before you finally close the tray.
If the problem with map definition is permanent and not solved by software, it may be a hardware malfunction of the module or connector, in which case the best solution will be diagnostics by specialists.