How to insert SIM- card in Xiaomi Redmi 4X: instructions with photos and secrets

Introduction: Why the correct installation of SIM- cards in Redmi 4X is so important

Xiaomi Redmi 4X (codename santoni) is still popular even years after its release, thanks to its reliability, maintainability and support for custom firmware. However, many users face difficulties when first installing the SIM- card: the tray is not removed, the card is not recognized or the phone says “No network”, the reason most often lies in the wrong format SIM or careless handling of the tray.

In this article, you will find not only step-by-step instructions with the photo, but also hidden nuances that are not written in the official manuals. For example, why the Redmi 4X can not see the second SIM- card even when installed correctly, or how to avoid breakage of the slot contacts. And we will also discuss the unique feature of this model: a combined slot for two nano-SIM or one SIM + microSD - and why this affects the choice of the operator.

If you just bought a used Redmi 4X or pulled it out after a long downtime, don’t rush to insert the SIM at random. Five minutes of careful reading will save you an hour searching for a service center.

Which SIM- card does Xiaomi Redmi 4X support: nano, micro or standard?

The slot for the SIM- cards in the Redmi 4X is designed exclusively for the nano-SIM format (4FF).

• 📱 Micro-SIM (3FF) or standard-SIM (2FF) won't work without being trimmed. Even if you force them in, the contacts won't match, and the phone won't see the network.
• ✂️ If you only have a micro-SIM, you can trim it to nano-format with a special stack (sold in communication salons) or scissors — but this is risky (see the warning below).
• 🔄 Redmi 4X slot has two slots: one for nano-SIM 1, the other for nano-SIM 2 or microSD (but not simultaneously!).

⚠️ Warning: If you decide to trim the micro-SIM to nano-format yourself, use the official GSM Arena template. An error of even 0.5 mm will lead to the card hanging in the slot or, conversely, will get stuck. In service centers, such "homemade" pull out for 500-1000 rubles.

How do you check your SIM format? Take a card and compare it to a coin.

• 🪙 Standard-SIM (25×15 mm) is the size of a penny.
• 🪙 Micro-SIM (15×12 mm) is like a quarter-five.
• 🪙 Nano-SIM (12.3×8.8 mm) is like a little fingernail.

Preparation for installation: what you need and how to avoid errors

Before opening the slot for the SIM- card, prepare everything you need. This will save you from typical problems such as a jammed tray or damaged contacts.

You will need to:

• 📱 The Xiaomi Redmi 4X smartphone itself (off!).
• 🔑 A paperclip or needle to extract the tray (complete with the phone, but often lost) will also fit an unbended paperclip or toothpick.
• 📇 Nano-SIM (one or two if you don't use microSD)
• 🔦 Flashlight (optional) – to better view the slot, especially if the used phone and it has accumulated dust.

Critically, don’t put the SIM- card in your phone. While many models support the hot replacement SIM, the Redmi 4X can damage the slot contacts when power is on, due to the design of Xiaomi 2017’s budget smartphones of the year.

⚠️ Warning: If you bought a Redmi 4X handheld, make sure you check before installing SIM to see if the metal tongue in the slot is bent. This is a common problem with carelessly extracting the tray. If the tongue is bent, the slot will have to be disassembled — it is almost impossible to do this at home without special tools.

Step-by-step: how to open the slot and insert the SIM- card in the Redmi 4X

Now, to the process itself, follow the instructions in strict order to avoid breakdowns.

Step 1. Turn off the phone.

Press the power button and select Turn off. Wait for the screen to turn off completely (usually takes 5-10 seconds).

Step 2. Find a slot for SIM-map.

In Redmi 4X, it is located on the left end (when you look at the screen with your face), and next to it there is a small hole for the paper clip.

Step 3. Remove the tray.

Insert the paperclip into the hole and press with force until the tray extends to the 1-2 mm. Then gently pull it with your fingers. Do not exert excessive effort - if the tray does not go, check if the old SIM- card is stuck inside.

Step 4. Set it up. SIM-map).

Place the tray on a flat surface. Notice the notch in the corner, which should match the notch on the tray. The SIM- card is set by the contacts down (the metal part should be visible).

Installation options:

• 📶 One SIM - insert it into the nest SIM 1 (usually marked on the tray).
• 📶📶 Two SIM – Use both nests, but remember that Redmi 4X does not support simultaneous operation of two 4G (the second SIM will only be in 2G/3G).
• 📶💾 SIM + microSD - insert SIM into SIM 1, and the memory card instead of SIM 2.

Step 5, put the tray back in place.

Carefully insert the tray back into the slot before the click. make sure it sits flat - if the tray is skewed, the SIM- card will not contact the phone.

Step 6, turn on the phone.

Press the power button and wait for the download. If done correctly, the network indicator will appear in the status bar.

1. Is the card inserted correctly (contacts down!).

2. Is there any oxidation slot on the contacts (green coating).

3. Whether the metal tongue in the slot is bent.-->

Common Mistakes and How to Avoid Them

Even with the seemingly simple process, many users make mistakes that lead to network loss or phone breakdown, and the most common ones are:

Particularly noteworthy is the problem with “no network” after installing the SIM correctly. 80% of cases are due to:

• 🔄 Non-activated SIM- card (especially if you just bought one) Solution: call from another phone to the new SIM number or check the status in the operator's personal account.
• 📡 Incorrect network settings. Go to Settings → SIM-maps and mobile networks → Access Point settings (APN) and select automatic settings.
• 🔋 Fail IMEI (relevant to used phones after firmware). Check IMEI by dialing *#06#. If zeros are displayed instead of a number, recovery is required.

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If the Redmi 4X doesn’t see the second SIM- card, but the first one is normal, try swapping them. In this model, the SIM 2 slot is less reliable due to the common microSD bus.

What to do if the SIM- card is not recognized: diagnosis and solutions

If after installing the SIM- card, the phone says "No SIM- card" or "No service", do not panic.

1. Reboot your phone. Sometimes the modem malfunctions are fixed by simply restarting. Press the power button for 10 seconds until the phone turns off, then turn it on again.
2. Check the SIM- card on another phone. If the card doesn't work, there's a problem with the operator. If it works, the Redmi 4X slot or modem is faulty.
3. Clear the SIM- contacts of the card and slot. Take a pencil eraser and gently rub the gold contacts on the SIM- card. Use a cotton swab dipped in alcohol to clean the contacts in the slot.
4. Reset network settings. Go to Settings → System → Settings Reset → Network settings reset. This will remove stored Wi-Fi and mobile network settings, but often helps with software failures.

If none of these things work, the problem could be hardware. Redmi 4X is the one that fails most often:

• 🔌 Card slot SIM- - oxidation or mechanical damage to contacts.
• 📡 Antenna module — especially if the phone falls or gets wet.
• 🔋 Qualcomm Snapdragon 435 modem requires flashing or repair.

⚠️ Warning: If you suspect a hardware malfunction, don't try to disassemble the Redmi 4X yourself. In this model, the display and battery plumes are very fragile, and replacing them will cost more than repairing in the service (from 1500 rubles).

Operator Compatibility: Which SIM- Cards Work Best

Xiaomi Redmi 4X supports 2G networks (GSM/GPRS/EDGE), 3G (WCDMA), 4G (LTE), but there are nuances with different operators:

Important point: Redmi 4X does not support 5G, and also has restrictions on the simultaneous operation of two SIM in 4G. If you insert two SIM- cards, then:

• 📶 SIM 1 can work in 4G, and SIM 2 can only work in 2G/3G.
• 🔄 If you are actively calling on one SIM, the second will not be available (no support for DSDS – Dual SIM Dual Standby).
• 📞 If you are interested in calling both SIM, it is better to use SIM1 for the main number and SIM2 for the Internet.

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To check which SIM- card is active for mobile internet, go to Settings → SIM- Cards and Mobile Networks → Mobile Traffic. Here you can select the priority SIM for data.

FAQ: Answers to Frequent Questions about SIM-maps 4X