Redmi smartphones have long proven to be reliable devices, but the procedure of initial activation of communication for new users sometimes raises questions. the Redmi 4 model, released back in 2016, has a classic case design, but requires care when working with a memory tray. Incorrect installation can lead to the fact that the phone will not see the network or damage contacts.
In this article, we will discuss in detail how to safely remove the tray, arrange SIM-map of the desired format and set up a priority slot for mobile Internet. You will learn about the technical nuances of working with a hybrid slot and understand why it is important to follow the direction of the plastic slice. Following the instructions will help to avoid mechanical damage and provide a stable signal from the first minutes of use.
The installation process takes only a few minutes, but requires care, and we'll look not only at the physical installation, but also at the software setup that's required to make two SIM cards work correctly at the same time, which is especially true for users who are actively using the separation of personal and work traffic.
Preparation of the workplace and tools
Before you start manipulating a gadget, you need to prepare the workspace, the surface should be flat, clean and well-lit, so that small details do not get lost or fall into hard-to-reach places, a bright table or a sheet of white paper will help you better see the contacts and orientation maps.
The main tool for retrieving the tray is a special paper clip that comes with the device. If the original key is lost, it can be replaced with a thin needle or an unstretched stationery clip, but you need to act extremely carefully. The use of too thick objects, such as a stitch or a knife, is strictly prohibited, as this can damage the mechanism of the spring inside the hole.
⚠️ Warning: Before removing the tray, make sure your hands are dry.Static electricity or moisture can negatively affect electronic contacts inside the slot, especially if the device has just been brought in from the cold.
It is also worth preparing in advance. SIM-Make sure it is the right size – Xiaomi Redmi 4 requires Nano-SIM. If your old card (Mini or Micro) is trimmed or replaced with a new one.
☑️ Preparation for installation
Tray design and card types
Redmi 4 is equipped with a hybrid slot, which is an important technical nuance.This means that the second slot can work either as a place for a second SIM card or as a slot for a microSD card, but not at the same time.
The tray is elongated and has two distinct card spaces. The first is usually for the main SIM card, the second is universal. It is important to pay attention to the shape of the cutout (skeet) on the plastic-based card. Modern standards use Nano-SIM, which is significantly smaller than its predecessors and does not have a chip on the back of the plastic.
| Parameter | Slot 1 (SIM 1) | Slot 2 (Hybrid) |
|---|---|---|
| Type of card | Nano-SIM | Nano-SIM or microSD |
| Support for 4G/LTE | Yes (main) | Yes (with a single SIM) |
| Simultaneous work | It always works. | Only with SIM or only with memory card |
| Hot-swap (replacement on the move) | Not recommended | Not recommended |
The location of the contacts on the map should be strictly consistent with the scheme on the tray. The gold chip always heads down to the contacts of the phone, while the plastic base looks up. It is almost impossible to confuse the sides physically, unless you make excessive efforts, since the cutouts on the tray repeat the contours of the map.
Can we use adapters?
Step-by-step installation instructions
The installation process begins by finding a tray extraction hole. On the Xiaomi Redmi 4, it is located on the top end of the device, to the left of the headphone jack (if you look at the screen). Insert the clip point into the hole perpendicular to the body and press until the characteristic click.
Once the tray is partially extended, carefully remove it with your fingers. Place the card in the appropriate recess, keeping the angle of the bevelled angle in mind. Make sure the card is tight and does not stagger. If you use the memory card, it is placed in the second socket on top of or instead of the contacts of the second SIM card.
Put the tray back in the phone, and it's important not to mix the top and bottom, and not to put it backwards, but to go in smoothly, without resistance, push it to the end until it's equal to the body of the device, and then you can turn on the smartphone.
⚠️ Warning: Don't try to force the tray if it doesn't enter. Remove it again and check orientation. Forced indentation can break the internal guides or damage the motherboard.
Network settings after installation
Once the device is turned on, the system will automatically detect a new SIM card. PIN-If you have the code, you'll have a request to enter it on the screen, enter the code provided by the operator to unlock access to the network, and if you enter the code three times incorrectly, you'll need to enter the code three times incorrectly. PUK-code.
To manage two SIM cards, you need to go to the settings. Go to the Settings menu, then select Two. SIM-Maps and mobile networks. Both maps are displayed here, and you can give them names like "Work" and "Personal" so you don't get confused in notifications.
Special attention should be paid to mobile Internet configuration. In budget models of the period, such as Redmi 4, high-speed 4G Internet often runs on only one card. You need to explicitly specify which SIM card will be used for data transfer. This is done by switching the radio button in the Internet section.
Path to menu: Settings → Two SIM- maps and mobile networks → Internet → Select SIM 1 or SIM 2You can also set up your preferred network type on this menu. For maximum speeds, select LTE mode Preferably. If the signal in your region is weak, you can switch to 3G or 2G to save battery power and a more stable, albeit slow, connection.
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To quickly switch mobile internet between SIM cards, add the SIM Switch widget to the home screen, allowing you to change the source of traffic in one click without diving into the settings.
Addressing common problems
Sometimes, after installation, the map is not detected or the network is missing. First, check if the tray is inserted correctly. Even microscopic skewing can disrupt the contact. Remove the tray, wipe the SIM card contacts with soft dry cloth and insert again.
If the phone says "No service" or "Emergency calls only," check the network settings. Make sure that "On the plane" mode is not turned on. It's also worth trying to manually select the carrier in the mobile menu, turning off automatic selection. Sometimes this helps to "grab" the tower.
The problems may be related to a software failure of the MIUI firmware. In this case, a simple reboot of the device helps. If this did not help, try installing the SIM card in another phone to rule out its physical malfunction. If the card is working on another device, the problem may be in the slot of your Xiaomi.
⚠️ Warning: Do not use metal objects to clean the SIM card contacts.The metal can leave microscopic scratches on the chip or create a static charge that can knock the card out of action forever.
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If the SIM card is not identified after all the checks, it may be cropped incorrectly and the chip is damaged, in which case the only solution is to replace the card in the operator's office.