Installation SIM-The cards in modern Xiaomi Redmi smartphones are the first and most important step after unpacking the device. Despite the apparent simplicity of the procedure, owners often face non-obvious nuances, such as combined slots or non-standard tray sizes. MIUI, the company's shell, has its own network recognition features, which must be taken into account when initially configuring.
In this article, we will discuss how to safely remove the tray, determine its type and correctly place the chip to avoid damage to the contacts. You will learn about the differences between hybrid and dedicated slots, as well as how to adjust the mode for two numbers.
Incorrect installation can cause the phone to stop seeing the network or quickly discharge in search of a signal, following simple rules of installation and subsequent software configuration ensures stable communication and access to mobile Internet at maximum speed.
Definition of tray type and preparation of tools
Before picking up a paperclip, you need to carefully study the design of your Xiaomi Redmi. Depending on the year of release and the price segment of the model, the manufacturer uses different configurations of slots. Most often, hybrid versions are found where one of the slots is combined with a slot for a microSD memory card.
Carefully look at the end of the case. The tray can be on the left or right, and in some moisture-proof models it is hidden under a rubber plug. The extraction uses a special key-clip that comes with the kit, or a thin needle. It is important not to use sharpened objects like stationery buttons, so as not to damage the latch mechanism.
⚠️ Warning: Make sure the phone is turned off before removing the tray. Although current standards allow hot replacement, the risk of short circuits in careless extraction still exists.
There are three main types of trays found in the Redmi line:
- 📱 Dedicated double: two independent slots for two SIM cards, the memory card is installed separately.
- 💾 Hybrid: In the second socket, you can install either a second SIM card or a microSD memory card at the same time.
- 🔒 Triple (rare): separate locations for two sims and a memory card, typical of some old or specific models.
Understanding your slot type is critical if you plan to use external memory. In hybrid models, the choice is between number two and storage expansion, as it is impossible to physically install both elements simultaneously.
Step-by-step instructions for installing a SIM card
The installation process requires precision and attention to detail. The standard procedure is to find a hole on the end of the case, insert the key perpendicularly and slightly press until you click, the tray will extend a few millimeters, after which it can be removed with your fingers.
☑️ Pre-installing check
Put the extracted tray on a flat surface. Notice the bevelled angle, which is a guide and will not allow the chip to be installed incorrectly. Carefully insert the Nano-SIM into the appropriate recess, the chip should lie tight, not staggering, but not being squeezed with force.
If you have a hybrid slot and you use a memory card, it is installed on top of the contacts of the second SIM card or in the adjacent socket, depending on the design. In some Redmi models, the contacts of the memory card are located on the back of the tray, which requires special care when building.
After placing all the elements, gently insert the tray back into the phone. Make sure it comes in smoothly, without resistance. If the tray doesn't go, don't press - you may be inserting it with the wrong side or skewing it.
What to do if the tray is not moved?
When the tray is fully recessed, you can turn on the device. Android must identify a new SIM card within 10-15 seconds of booting. If this does not happen, check the correct installation of the chip or try to wipe the contacts with soft cloth.
Setup of two SIM cards in MIUI
After successfully installing two SIM cards, the user is asked how to set them up optimally, and the MIUI shell offers flexible management tools that allow roles to be distributed between numbers, typically one number being used for calls and the other for mobile Internet.
To set up, go to the Settings menu → SIM-You'll see a list of installed cards here, and if you click on a particular SIM card, you can name it (e.g., "Work" or "Personal"), which will make it easier to identify when outgoing calls.
The important thing is to choose the default card, so you can configure the system so that all outgoing calls are made from one number and the Internet works through another, and you can also use the Always Ask feature, which will request a selection of a SIM card before each call.
Special attention should be paid to the configuration of VoLTE and HD-If your carrier supports these technologies, activating them will greatly improve the quality of communication. In the SIM card settings menu, find the appropriate switch and activate it.
Typical problems and methods of their solution
Even with the right physical setup, software failures can occur, and the most common problem is that the phone says "No network" or "Emergency Calls Only." In this case, the first thing you should do is check if the SIM card itself is on in the settings, and sometimes after you update the system, the card activity switch can reset.
If the phone sees the SIM card but doesn't catch the network, try manually selecting the operator. → SIM-maps and mobile networks → Select the operator and turn off the automatic mode. Wait for the search to end and select your provider from the list.
| Problem. | Possible cause | Decision |
|---|---|---|
| Can't see the SIM card. | Contact contamination | Rub the chip with alcohol, insert again |
| Continuous search of the web | Wrong type of network | Select "Preferred to be 4G" |
| No Internet. | Not configured access point | Reset APN settings to factory |
| SIM card blocked | Incorrect PIN input | Enter. PUK-operator |
Another common situation is the blocking of PUK-This happens after you've entered three times incorrectly. PIN-code. PUK-The code can be found on the plastic card, which was included with the SIM card, or find out in the operator’s personal account.
⚠️ Attention: Don't try to guess PUK-After 10 wrong attempts, the SIM card will be permanently blocked and cannot be restored - you will have to buy a new one from the operator.
Features of working with 4G and 5G networks
Modern Xiaomi Redmi smartphones support high-speed communication standards. However, to work on 4G (LTE) and 5G networks, it is not enough just to have support in your phone. Your tariff plan should include access to these networks, and the SIM card should be of the appropriate generation (usually USIM).
If you have a very old SIM card that was released more than 10 years ago, it may not work properly on 4G networks. In this case, it is recommended to replace it in the carrier cabin, retaining your number.
💡
Use the ##4636## command to log into the engineering menu, where you can force your phone to switch to LTE Only mode if the network is constantly falling on 3G.
In the mobile network settings, you have Network Type. For maximum speed, select "LTE Preferred" or "5G Preferred." However, in areas of uncertain reception, forced 4G activation can lead to faster battery discharge, as the phone will constantly search for a signal.
Carrier Aggregation, supported by many Redmi models, allows multiple frequency bands to be combined to increase speed, which works automatically if it is supported by the operator and the selected tariff.
Data security and SIM card locking
Protecting access to your SIM card is an important aspect of digital hygiene. PIN-The code will prevent your number from being used on another device in the event of a phone theft, and without knowing the code, the attacker will not be able to make calls or receive any phone calls. SMS confirming banking operations.
You can activate the protection in the Settings section. → Protection SIM-When this function is enabled, the code will be requested every time you restart your phone, write it down to a secure location, as it cannot be restored through the operator.
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PIN-The default code is often 0000 or 1234, but it is better to change it to unique in the security settings.
Also worth mentioning is the SIM-change lock feature, which is found in some Xiaomi antivirus and security system settings, which allows you to send a notification to a trusted number if a new SIM card was inserted into your phone without your knowledge.
Regularly check the list of active devices in the personal account of your mobile operator, this will help unauthorized cloning of the SIM card or connecting additional services.