The situation when modern Xiaomi stops seeing SIM-The card often takes the user by surprise, the communication indicator may disappear completely, or a crossed-out icon will appear in the status bar, making it impossible to make calls and access the Internet. This is a critical problem for a device that is inherently a communicator.
The causes can range from the banal physical contamination of contacts to complex software failures in MIUI. Before carrying a gadget into the service, it is worth conducting an independent diagnosis, and in most cases, the problem can be solved without professional intervention, if you act consistently and correctly.
In this article, we will look at all possible scenarios for failure of the system to work with the communication module, you will learn how to check the integrity of the tray, configure access points, and whether to contact the operator. Systematic search methods from simple to complex can eliminate 90% of login errors in the network.
Primary Diagnosis and Physical Examinations
The first thing to do when you find a problem is to rule out mechanical damage. Often, the smartphone simply loses contact with the chip due to vibration or dust. Carefully remove the tray with a paper clip and inspect it. There should be no oxides, dirt or scratches on the metal pad.
Pay attention to yourself. SIM-If it's been in use for a long time, its contacts may have been erased or covered with fat film. Rub the chip with a soft dry cloth. Also check if it's properly installed in the tray - the angle bevel must match the notch in the holder.
It's important to check the integrity of the tray itself. In moisture-proof models or just thin cases, the tray can deform when it's not extracted carefully, and if it staggers or enters with great difficulty, the geometry of the sled inside the shell may be disturbed.
⚠️ Warning: Never put the tray back in if it's not on it SIM-A card or plastic stub, and dust entering the connector can short the contacts of the reader.
☑️ Diagnosis of physical condition
After physical check, turn on the device. If a Redmi or Poco phone still doesn't see the SIM, go to software methods. Often, the system just doesn't have time to initialize the communication module after booting.
Software settings and network reset
If the map is physically intact, the problem may be a software failure. Android sometimes freezes in an attempt to read the operator's data. The fastest way to fix this is to switch modem mode.
Go to the settings and select a paragraph «SIM-Maps and mobile networks. Try to force the network type to change. 5G/LTE, change to 3G/2G. If after that there are “rods” of the signal, then the problem is in the coverage or frequency settings.
The effective method is to completely reset your network settings. This action will not delete your personal photos or contacts, but will return your Wi-Fi, Bluetooth and mobile settings to factory values. The path to the feature is usually at: Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth.
Why does resetting the net help?
Once it's reset, it'll reboot, it'll re-request the operator, and if you're using a dual-sim phone, check if the desired slot in the control menu is activated. SIM-Sometimes users accidentally turn off the second SIM and then forget about it.
Compatibility issues and SIM form factor
Modern Xiaomi smartphones work with Nano-SIM cards. If you use a Micro-SIM adapter or, worse, cut the card yourself with scissors, this can be the reason for failure.
Older cards released 5-7 years ago may not support modern encryption protocols or frequency bands that your new Xiaomi 13 or Redmi Note 12 uses.
- 📱 Use only the original Nano-SIM format without thickening.
- 🔄 Replace the card over 5 years in the operator’s office for free.
- 🚫 Avoid using adapter adapters in the slot.
In some regions, combined trays of "2 SIM + MicroSD" or "1 SIM + 1 SIM + MicroSD" are popular. Make sure you insert the card into the correct slot designed to work with 4G/5G networks if the second slot only supports 2G.
Access Points and APN settings
Often the phone sees the SIM card, logs in, but the Internet doesn't work, and the user thinks the card is not defined. This is a classic APN configuration error. Without the right settings, the phone doesn't know which gateway to send data through.
Check the current profile of the access point. Go to Settings → SIM-maps and mobile networks → Choose. SIM → Access points (APN). Your carrier profile should be active here, and if the list is empty or the wrong profile is selected, the Internet will not work.
The easiest way to fix this is to click the Reset button (usually an icon with three dots or arrows in the APN menu), which automatically downloads current parameters from the operator's server, manually entering values is rarely required and only at specific corporate rates.
| Operator. | APN name | Type APN | Note |
|---|---|---|---|
| MTS | internet.mts.ru | default,supl | Standard for the Russian Federation |
| Beeline | internet.beeline.ru | default,supl | Authorization required |
| MegaFon | internet | default,supl | No login/password required |
| Tele2 | internet.tele2.ru | default,supl | It works automatically. |
Once you have set up the settings, be sure to turn on and off Airplane Mode, which will force you to reconnect the communication module with the updated settings, and if the 4G/LTE icon appears, the problem is solved.
Impact of MIUI Updates and Firmware
Xiaomi users are well aware that MIUI or HyperOS updates sometimes bring new bugs. Once a new firmware version is installed, the phone may stop correctly identifying SIM cards of certain operators or regions.
If the problem appears immediately after the update, try to clear the phone and settings system application data. This won’t delete your contacts, but will reset error logs. Go to Settings → Apps → All applications, find system services and click Clear.
In rare cases, flashing the device to the global version (Global) helps if you are using the Chinese version (CN). Chinese versions may not support Band 7 or Band 20 frequencies, which are critical for 4G operation in Europe and the CIS, which makes the phone "cannot see" the network.
⚠️ Warning: Flashing from Global to China or vice versa requires unlocking the bootloader.This action can lead to loss of warranty and data if no backup is made.
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Before installing a major MIUI update, always back up your contacts to your Google account, as resetting your network settings can delete local entries.
Hardware malfunctions and repairs
If none of the software methods worked, the probability of hardware failure is high. In Xiaomi smartphones, especially after falls, the plume of the antenna module can move away or the SIM reader itself can be damaged.
A common problem is that the contacts inside the phone oxidize because of moisture. Even if the phone hasn't sunk, high humidity in the bathroom or outside can cause corrosion. Visually, this may be invisible, but the contact will disappear.
It's also worth checking the motherboard for microcracks, because if you hit it hard, it could be that the radio contacts would go away, and then you need to have a multimeter and microscope diagnostic at the service center, and if you repair it yourself without experience, you can actually get the device out of action.
- 🔍 Check if the contacts are bent in the depth of the slot.
- 💧 Look at the moisture indicators (usually white circles inside).
- 🛠 If you suspect chip dump, warm-up or soldering is necessary.
In some cases, it helps to clean the connector carefully. SIM-If you have alcohol and a toothbrush, you should do it with your phone off and your battery off (if possible.
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If the phone does not see the SIM card after falling or getting water, software methods are powerless - hardware diagnostics are required and, probably, a replacement of the connector.