How to insert a second SIM in Xiaomi Redmi 4

Smartphones Redmi 4 series from Xiaomi deservedly considered one of the most popular budget devices of its time. Their reliability and affordable price made these gadgets a real hit, but new owners often have confusion with the organization of slots for memory cards and other devices. SIM-The question of how to insert a second sim, becomes especially relevant, because the design of the tray here has its own unique features that distinguish it from more modern models.

Unlike many modern devices that use a combined slot or a fully virtual eSIM, Xiaomi Redmi 4 uses a classic mechanical tray, but with an important nuance: Proper installation of the second card provides stable communication and the ability to use two numbers simultaneously, which is critical for separating work and personal calls. In this article, we will discuss the installation process, types of trays and software configurations.

Types of trays and design features of Redmi 4

Before you start physically installing cards, you need to clearly understand what modification of the device you are dealing with.The Redmi 4 line includes three main versions: basic, Prime and Pro. SIM-The cards may vary slightly, which directly affects the installation of the second SIM. In most cases, a retractable tray located on the lower or upper end of the case, depending on the specific revision of the board.

The main difference is that the Redmi 4 is designed to support communication standards and the size of the cards themselves. Micro-SIM cards are the standard for devices of the period. It is important not to confuse this slot with newer models that have already used the Nano-SIM format. Using an improperly sized card can lead to a tray getting stuck or damage to contacts inside the smartphone.

There is also a difference in 4G support. Some tray versions allow both slots to run in 4G mode, but only one at a time, while the second moves to 2G/3G. Other modifications may have restrictions where the second slot operates exclusively in 2G mode. This is a hardware technical limitation that must be considered when planning to use tariff plans.

• 📱 Basic version: often has a combined slot where the second slot shares space with a microSD card.
• 🚀 Prime version: usually equipped with a separate microSD slot, allowing you to use two SIM-maps and memory simultaneously.
• ⚡ Pro version: supports higher data rates and has an improved antenna system for two sims.

⚠️ Warning: Never try to insert a microSD card into a slot designed only for the purpose of SIM-This will short the contacts and cause permanent damage to the motherboard.

To remove the tray, a special metal clip is provided with the device, and if it's lost, you can use a regular paper clip to straighten one of the ends of the tray, and the main requirement for the tool is that it has enough stiffness and a thin diameter to activate the mechanical pusher inside the hole.

Preparation of tools and maps for installation

The process of installing a second SIM requires a minimum set of tools, but the preparation must be thorough.First of all, make sure your smartphone is completely off. SIM-maps for Xiaomi Redmi 4 and its version of the operating system MIUI At that time, it is safer to manipulate the power out to avoid software failures of the network definition.

The second important step is to prepare for SIM-If your card is new (Nano-SIM) and your phone requires a Micro-SIM, you'll need a special plastic adapter, but using adapters doesn't always guarantee stable contact, especially when you're using your phone. It is better to contact the operator’s communication salon to replace the card with a Micro-SIM format.

Check the contacts on the golden part. SIM-They should be clean, free of oxides, grease or scratches. If there is any contamination on the map, gently wipe it with a dry soft cloth or a weasel. Alcoholic liquids are permissible, but only if the card has time to dry completely before installation.

You also need to determine which slots will be the primary one, and in MIUI settings you can change their priority for calls and the Internet, but physically, the cards are better placed according to the logic of use, usually SIM 1 is for the main number, and SIM 2 is for additional traffic or work calls.

Step-by-step: installation of the second SIM-map

Now, to the mechanical part of the process, find a small hole on the smartphone body next to the card tray. In Redmi 4, it is usually located on the lower end, to the right of the Micro-USB connector. Insert the clip point into the hole perpendicular to the body and press until the characteristic click.

The tray should extend a few millimeters. Carefully pull it with your fingers, trying not to damage the rubber seal if it is present. You will have two seats in front of you. Depending on the model, they can be located next to each other or one above the other. Pay attention to the shape of the cutout in the corner of the tray - it corresponds to the beveled corner SIM-map.

Put the second down. SIM-Make sure it lies flat and doesn't protrude above the edges of the tray. If the card lies above the level of the sides, you can't put the tray back in without an effort that can break the mechanism.

💡

If the tray is tight, don't push hard. Take it out and check if it's lying right. SIM-map and whether the pile got inside the hole.

After installing the tray, turn on the smartphone. Android system should detect a new one. SIM-You'll see a sign-up notice on the screen, and if you're using different carrier cards, make sure that both networks are found. PIN-card-unlock.

Set-up of two SIM-card MIUI

After successful physical installation, you need to properly configure the software part. MIUI offers flexible tools for managing two numbers. Go to the Settings menu → SIM-Maps and mobile networks. Here you'll see a list of installed maps and their performance parameters.

First, activate the second one. SIM-If the card is not automatically activated, switch the switch to the "On" position, then you need to configure the use cases, the system allows you to choose which card will be used by default for voice calls and which for mobile data.

In Redmi 4, only one card can work in 4G/LTE mode at a time. If you choose SIM 2 for the Internet, and it only supports 2G/3G in your configuration, the speed will be low.

Smart Limits is also available, which allows you to turn off the second SIM at a given time or when the battery is low, which helps save energy. For the Redmi 4 with its capacious battery, this is not critical, but the option is useful for extending the battery life in standby mode.

⚠️ Note: When activating the mobile Internet on the second SIM-The first card can automatically switch to mode. 2G. This is normal behavior for modems of that generation, not a malfunction.

Be sure to check your data roaming settings if you are planning a trip. For a second SIM, which is often used as an optional one, roaming data is best kept off to avoid accidental chargebacks.

Solving Common Problems with Network Definition

Even if installed correctly, there can be situations where the second SIM is not detected or is not functioning properly. One of the common causes is contamination of the contacts in the tray itself or on the map. Try to extract the cards and wipe the contacts with a wipe, removing the oxides. Also check if the tray itself is deformed.

If the phone sees the map but writes "No Network" or "Emergency Calls Only," the problem may be settings on the network modes. → SIM-maps and mobile networks → Preferred network type: Make sure you select "Preferred" LTE» or «4G». Sometimes it helps manual selection of the operator in the menu "Telecommunication operators».

There are cases when a software failure MIUI It blocks the second slot, and then it helps to reset the network settings, and it doesn't delete your personal data (photos, contacts), but it does return all the settings of Wi-Fi, Bluetooth and mobile networks to factory settings. → Advanced settings → Recovery and discharge → Resetting Wi-Fi, Mobile Internet and Bluetooth settings.

If nothing helps, check it out. SIM-If the card is working on the other device, and Redmi 4 is not, it may be that the reader is damaged. SIM (SIM-reader) on the motherboard, which requires repair in the service center.

Features of Internet use and calls

Using two SIMs imposes certain limitations on the communication architecture. As mentioned, Redmi 4 has a technology that allows you to receive calls to both cards at the same time, but active voice conversation is possible only on one. If you call the first SIM to the second, you will hear a “busy” signal or see an incoming notification, depending on the operator’s settings.

Switching between SIMs for calls can be done directly from the contact menu or at the time of dialing. The dialing interface usually has buttons "SIM 1" and "SIM 2". You can also configure automatic selection: for example, always call contacts from the "Work" list through the second SIM, and personal ones through the first.

As for the speed of the Internet, Xiaomi Redmi 4 is able to provide quite comfortable surfing. However, when you actively download files through the second SIM, the first one can temporarily lose connection to the Internet, although voice calls must pass. This is a feature of the radio module, which can not simultaneously transmit data and voice on 2G/3G networks on the second line.

💡

For maximum stability, use a single carrier card or a good 4G card in your area, as switching between different carrier towers consumes more energy.

Watch the indicators in the notification curtain, which displays which SIM the data is transmitted through (usually the arrows up and down are illuminated by the color of the corresponding SIM), which helps to control traffic flow so as not to go into the red on the main tariff.

Maintaining contacts and synchronization

With two numbers, it is often a question of where to save new contacts. Android can offer a default choice: save to SIM 1, SIM 2, phone memory or Google account. Redmi 4 owners are strongly recommended to use sync with a Google or Mi Cloud account.

Maintaining contact directly to SIM-The card has a number of restrictions: the card only stores the number and name (often with a length limit), but no email, addresses, photos and additional numbers are stored.

If you do decide to store contacts on a SIM, remember that there is a limited amount of memory (usually up to 250 records). When you overflow, you can not save new records. Regularly back up contacts from SIM memory to your phone memory through the Contacts → Import / Export menu.

• ☁️ Google Contacts: The Best Option, Syncs All Data and Restores It on Any New Phone.
• 📱 Phone Memory: Stores advanced information, but is lost when you completely reset your settings without a backup.
• 💾 SIM-card: universal but limited format, suitable for base reserve.

Competent tuning and understanding of the principles of the two SIM-Xiaomi Redmi 4 cards will allow you to make the most of the capabilities of this smartphone. Compliance with installation rules and regular contact maintenance will ensure stable communication in all conditions.