Modern smartphones, including Xiaomi’s popular Redmi 4, require the right setup of communication modules to work properly. Many users face difficulties in first setting up the device, especially when it comes to retrieving and installing it. SIM-Wrong actions can damage the tray or the chip itself, so it is important to be careful and have a clear algorithm for action.
In this article, we will take a closer look at where the SIM slot in Xiaomi Redmi 4 is, which side to put it on, and how to avoid common errors. You will learn about the differences between card formats, the features of hybrid trays, and how to diagnose network-detection problems. Remember that the Redmi 4 has a hybrid slot, where the second one is the second one. SIM-The slot can be replaced with a microSD card, but you can not use them at the same time.
Before you start physically affecting the body of the device, make sure you have all the necessary tools at hand. Usually a special paper clip is included with the phone, but if it is lost, a thin needle or an unbended stationery clip will fit. The main thing is to act carefully so as not to scratch the aluminum body or damage the extraction mechanism.
Tool preparation and choice of map format
The first step before installing a communication card is to prepare the workspace and tools. You will need a sharp but thin item to extract the tray. Xiaomi standard includes a metal clip with a rounded end, which is perfect for a hole next to the slot. If there is no original key, you can use a regular sewing needle, but be extremely careful not to pierce your fingers and damage the internal mechanisms of the phone.
You also need to make sure that your SIM-The Redmi 4 series of smartphones work with the Nano-SIM standard, which is the smallest of the existing sizes. If your card was cut from a larger format (Mini or Micro) or is older, its dimensions may not match the tray geometry. In such cases, it is better to contact the operator’s communication salon for a free replacement with Nano-SIM, which guarantees a perfect landing and no problems with contacts.
Pay attention to the state of the chip. The gold contacts must be clean, without oxidation, scratches and greasy spots. If you just received a new card, make sure that the protective film is removed. Dirt on the contacts can cause the phone to stop seeing the network or permanently lose signal.
- 📱 Prepare the original paperclip from the kit or a thin needle to extract the tray.
- 💳 Make sure yours is yours. SIM-The card has the Nano-SIM format (smallest size).
- 🧹 Wipe the card contacts with soft dry cloth if they are contaminated.
- 🔌 Turn off the phone before installation to avoid software conflicts when determining the network.
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If you SIM-The card is too thick and doesn't enter the tray, so don't force it, it can damage the contacts inside the phone.
Slot location and extraction mechanism
In the Redmi 4 model tray for SIM-The map is located on the top end of the device, and unlike many modern smartphones, where slots are on the side, Xiaomi engineers chose the top placement, which is dictated by the design of the metal housing and the location of the internal antennas. To the left or right of the central headphone jack (if it is in a specific modification) or just on the edge you will find an oblong hole and a narrow slot.
To remove the tray, you need to insert the tool into a circular hole next to the slot. Press perpendicular to the face of the phone, clearly in the center of the hole. You need to feel a slight click of the spring mechanism, after which the tray will extend a few millimeters. Do not use excessive force: if the tray does not come out, you may have improperly hit the hole or use a too thick tool.
Once removed, take a close look at the tray. Redmi 4 has a specific design. On one side, there's room for one Nano-SIM card, and on the other, a combined slot. This combined slot can accept either a second Nano-SIM or a microSD memory card. It's important to understand that it's physically impossible to install two SIMs and a memory card simultaneously in this phone.
Orientation and correct installation SIM-map
The most critical point of the instruction is the correct orientation of the card in the tray. Many users make the mistake of trying to insert a SIM "at random", which can lead to short circuit or mechanical damage to the contacts. On the tray Xiaomi often has a micro-circuit or pictogram showing how the card should lie. If you look closely, you can see that the beveled corner of the card must coincide with the beveled angle in the tray.
The card is placed with the contacts (the golden part) down to the inside of the phone. The cut corner is usually in the upper left or lower right corner, depending on which slot you install it in. For the first slot (usually marked with a number 1), the card is inserted so that the contacts look at the phone screen (if you look at the phone from the back) or down if you look at the end. In the second slot, the orientation may differ, so always check the pattern on the plastic holder itself.
Make sure the card fits tightly to the plastic tray base and doesn't protrude above its edges. If the card lies above the plastic level, when inserted into the phone, it can get stuck or damage the contact pins inside the device. Carefully press the card with your finger to make sure it's fixed, but try not to touch the golden contacts with your hands, as skin oil can oxidize the metal over time.
⚠️ Note: Never put a tray in your phone if you SIM-The card or the memory card extends beyond the card, and this is guaranteed to cause the reader to break down.
☑️ Pre-insertion check
Install a microSD card instead of a second SIM
If you don’t need a second number, you can use a second slot to expand your internal memory. Redmi 4 supports memory cards up to 128GB (in some firmware and more), allowing you to store thousands of photos, music and video. The installation process is similar to installing a SIM card, but there are important compatibility nuances.
Insert the microSD card into the combined slot with the contacts down. Make sure it snaps. Once the phone is turned on, the MIUI system will automatically detect a new drive. Unlike some other brands, Xiaomi allows you to format the card as internal storage or as a portable medium. The choice depends on your needs: formatting as internal storage will allow you to install applications on the card, but transferring them to another phone without losing data will be difficult.
It is worth noting that the speed of the memory card affects the overall performance of the smartphone. Cheap cards of low class can slow down the system, especially if they are installed applications. Redmi 4 recommended to use cards of class speeds at least 10 or UHS-I to ensure smooth interface and fast video recording.
| Parameter | Slot 1 (SIM 1) | Slot 2 (SIM 2/SD) |
|---|---|---|
| Type of card | Nano-SIM | Nano-SIM or MicroSD |
| 4G support | Yes (main) | Yeah (on switching) |
| Orientation of contacts | Down. | Down. |
| Max. SD volume | - | 128GB (officially) |
Turning on the phone and setting up the network
Once the tray is successfully installed back into the case (until a characteristic click), you can turn on the device. Press and hold the power button on the side. If the phone has been turned off, the Android operating system with the shell will start to boot. MIUI. During the boot process, the system will question the installed modules. SIM-The card is installed correctly, at the top of the screen (in the status bar) will appear signal level indicators and the operator name.
In some cases, especially when using the old SIM-maps, the system can request PIN-This is a security code that is set by the user himself or issued by the operator in a sealed envelope along with the card. PUK-code: PIN It is necessary to unlock access to the network, and PUK It is required only after three times incorrect input. PIN. Enter the code carefully, as several errors can block the card permanently.
If the network indicators don't show up, check the settings. Go to Settings. → SIM-maps and mobile networks. Here you'll see a list of maps installed. Make sure the switches are opposite the right ones. SIM-You can also choose from this menu which card will be used for mobile Internet by default and which card will be used for calling only. 4 It is important to manually select the preferred network type, for example, LTE, So that the phone does not get stuck in mode 2G/3G.
What do you do if you say "No network"?
Diagnosis and error elimination
Even if installed correctly, there can be situations where Xiaomi Redmi 4 can't see the SIM card. One of the common reasons is the oxidation of the contacts on the card itself or on the phone. Try gently wipe the SIM chip with a wipe or an alcohol wipe. It's also worth checking whether the tray itself is deformed: if it bends, the contacts may not reach the chip.
Another common problem is a software failure of the radio module, in which case resetting the network settings helps. Go to Settings → Advanced Settings → Restore and Reset → Reset the settings of Wi-Fi, mobile Internet and Bluetooth. This action will not delete your personal data (photos, contacts), but will return the network settings to factory values, which often solves the problem with registration on the network.
If the phone detects the card but does not catch the network 4G, Make sure your carrier supports the frequencies your particular machine is configured to. Redmi 4 came in multiple versions (Global, China, India) and they can differ in supported bands (Band). Also make sure that the service 4G activated on the tariff plan.
⚠️ Attention: If the phone suddenly stopped seeing both SIM cards after falling or getting moisture, the problem may be hardware.In this case, self-repair can aggravate the situation, it is better to contact the service.
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If the phone can't see the SIM, try inserting it into another phone first. If it doesn't work there, change the card from the operator, if it works, the problem is in the slot or the software of the smartphone.