Xiaomi Redmi mobile phone 4A, The device, which was released in 2016, is still popular today due to its reliability and affordable price, but for many users, especially those who are moving from button phones or older smartphone models, the process of installing a communication card can be a real challenge. Unlike the old machines, where SIM-The card was inserted under the battery, modern gadgets require a more delicate approach and the use of special tools.
Installing a communication chip incorrectly can cause the device to stop seeing the network, or worse, damage the tray itself or the contacts inside the smartphone. In this article, we will detail how to safely remove the tray, determine the correct size of the plastic and correctly install the communication module.
Before you start the physical impact on the case, you need to make sure that you understand the design of your device. Redmi 4A is equipped with a hybrid slot, which means the ability to install two SIM cards or one card and one microSD memory card.
Preparation of the workplace and necessary tools
Any electronic manipulation requires a calm environment and good lighting. Don't try to insert a SIM card on the run, in the dark or with trembling hands when you're in a hurry. Prepare a flat surface covered with soft cloth or towel, so that in the event of a fall, small parts like the tray or the SIM card itself do not get lost or scratched on a hard table.
To retrieve the tray, you'll need a special key-clip that comes with the phone. If the original tool is lost, you can replace it with a regular paper clip, straightening one of its ends, or a thin needle. The main requirement for the tool is that it must be thin enough to enter the hole, and strong enough to withstand pressure when extracted.
⚠️ Warning: Never use sharp objects like knives or sewers to remove the tray, and you risk piercing the body and damaging the internal components or battery, which can cause fire.
Also make sure your hands are dry and clean. Fat spots can contaminate SIM card contacts, which will cause the network to run unstable.If you wear glasses, put them on for a better view of fine details. Preparation takes only a couple of minutes, but significantly reduces the risk of error.
☑️ Preparation for installation SIM
Type and size determination SIM-map
Modern smartphones, including the Redmi 4A, work exclusively with Nano-SIM cards. It is the smallest standard of plastic cards for cellular communication to date. If you have been using the services of a telecom operator for a long time, you may have an old-format card (Mini or Micro) that physically cannot fit in the tray without damaging the contacts.
Visually, the Nano-SIM differs from its predecessors in that the plastic frame around the gold chip is virtually non-existent. The chip occupies almost the entire area of the card. If your card is larger, do not try to force it into the slot. You need to contact your operator's communication salon for a free replacement of the card with the Nano format or carefully trim the excess edges if you are confident in your skills.
- 📏 Mini-SIM, the largest format resembling a broken-angle credit card, was used in older phones.
- 📐 Micro-SIM – Medium size, was the standard for smartphones of the early 2010s.
- 💎 Nano-SIM is the minimum size required for Xiaomi Redmi 4A and most modern devices.
It is also important to check the status of the contacts on the map itself, they should be clean, without oxides and deep scratches. If the card looks damaged, it is better to get a duplicate from the operator, since poor contact can lead to constant network searches or complete absence of a signal.
Can I use an adapter?
The process of extracting the tray for SIM-map
Find a narrow horizontal hole on your smartphone. In the Redmi 4A, the SIM card tray is located on the top end of the device, next to the headphone jack. This is the one you need to insert the tool into. Be careful: there may be microphone holes nearby, which are often confused with a tray slot.
Take a paper clip or a key and insert it perpendicularly into the hole. You don't have to push too hard, but a light touch won't be enough. You should feel a slight click of the spring mechanism, after which the tray will push out a little. If the tray doesn't go out, try to change the angle of the tool slightly, but act carefully.
⚠️ Attention: If the tray is not removed with moderate pressing, do not use excessive force. You may have hit the wrong hole or the mechanism jammed.
After the tray is extended a few millimeters, gently pull it with your fingers over the edge. Try to pull it smoothly, without skewing, so as not to bend the metal guides inside the housing. Place the extracted element on the prepared surface with the outside up.
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If the tray is removed with difficulty, try to slightly tap the phone body on the palm at the time of pressing the paper clip - vibration will help the mechanism to work.
SIM installation scheme and memory card in hybrid slot
The design of the tray in Xiaomi Redmi 4A is hybrid, which means that the user has the choice of using two SIM cards at the same time or one SIM card and one microSD memory card to expand storage.
The tray has two positions. The first position (usually marked with the number 1 or has a shape that repeats the Nano-SIM circuit) is for the main SIM card. The second position (number 2) can be used either for the second SIM card or for the memory card. Note the shape of the cutout: the SIM card and the microSD have different geometries, and it is difficult to confuse them on close inspection.
When laying the card, it is important to observe orientation. Golden contacts should look down to the inside of the phone when you insert the tray back. The bevelled corner of the card should coincide with the bevelled angle of the notch in the tray. If the card does not lie flat, do not press it, then it is inverted or not oriented correctly.
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The hybrid slot allows you to choose the priority: either a dual SIM card or a single SIM card plus a maximum storage capacity of up to 128 GB.
Below is a table that helps you quickly navigate the slot configuration:
| Position in the tray | Type of card | Orientation of contacts | Note |
|---|---|---|---|
| Slot 1 | Nano-SIM | Down (inside) | The main slot for communication |
| Slot 2 (option A) | Nano-SIM | Down (inside) | For the second line |
| Slot 2 (option B) | microSD | Down (inside) | To expand memory |
| Both slots | 2x Nano-SIM | Down. | Dual SIM Mode is Active |
Inserting the tray back into the smartphone case
Once the cards are placed in their nests, you have to put the tray back in place, which is a critical point that requires carefulness, because the tray has a very specific side of the entrance, and if you try to insert it upside down or on the other side, it just rests in the case and does not enter until the end.
Look at the tray: one side of it has a small cutout or bevel that matches the shape of the hole in the phone. Combine this profile and smoothly, without jerking, push the tray inside. It should enter easily and before the click. If you feel resistance, don't push, take out the tray and try to turn it over.
A properly installed tray becomes flush with the phone body. No plastic parts should stick out. If the tray protrudes even a fraction of a millimeter, it can lead to dust and moisture entering the device, as well as to failure of the mechanism when carried in the pocket.
- ✅ Make sure that the angle of the tray matches the shape of the hole.
- ✅ Press evenly on the entire area of the tray, not on one edge of it.
- ✅ Check that the memory card or SIM card did not pop out of the socket when pressed in.
Initial configuration and verification of network operation
Once the SIM card is physically installed, you need to turn on the smartphone. Press and hold the power button on the side of the device until the screen lights up. The MIUI system (Android shell) starts to boot. The process usually takes about 30-40 seconds.
Once the phone turns on, look at the top status bar, and it should show up as bars and your carrier's name, and if you set up two cards, you'll have two indicators. If the operator's name is not the "No" sign. SIM-"Put in the cards" or "Put in" SIM", So the card is not readable.
In some cases, the system may request PIN-This is a security code that is set by the user himself. If you haven't changed it, try standard codes (often 0000 or 1234), but you'd better check with the operator. PIN-The phone is ready to go.
⚠️ Note: If the phone is requesting PUK-code after three incorrect attempts to enter PIN, Don't try to guess the code at random. Ten failed attempts to enter. PUK will lead to the blocking of the SIM card, and it can be restored only by re-release in the communication salon.
To check the Internet, try to open any website in your browser or run an application. If the pages do not load, make sure that the settings activate mobile data transfer. The path to settings usually looks like this: Settings → SIM-maps and mobile networks → Mobile Internet.
What if the phone only sees one of the two cards?
Frequent problems and ways to solve them
Even when installed correctly, there are technical difficulties, and one of the most common problems is that the phone stops seeing the SIM card after a while after turning on, which can be due to oxidation of contacts or software failure. Try to wipe the SIM card contacts with a soft wipe or an alcohol wipe.
Another common problem is the lack of a network. 4G. Redmi 4A It supports the fourth generation of communication, but it needs to work, the SIM card also supported this standard, and the appropriate mode was selected in the phone settings. → SIM-maps and mobile networks → Type of network and choose preferred 4G.
If the phone says "Unknown" SIM-This may mean that the device is tailored to a specific operator (this happens with phones imported from abroad). In the case of official Russian versions of Xiaomi, this problem is extremely rare.
- 🔄 Restart the device after installing the card.
- 🧹 Wipe the SIM card contacts with dry soft cloth.
- ⚙️ Check the settings of the preferred network type in the menu.