A situation when, after turning on a new smartphone or installing a new SIM card, a message appears on the screen “Sim card not activated”, can cause panic in any user. On Xiaomi, Redmi and Poco devices, this problem is common enough and can be caused by both software failure and hardware limitations. IMEI-communication module code or does not receive a response from the operator's base station.
It is important to understand that this error cannot be ignored, since without active SIM-The phone is turning into a media player without the ability to make calls or mobile Internet, and in most cases, you can solve the problem yourself without going to the service center. IMEI-code that identifies your device in the operator’s network.
The next steps depend on the specific model of your gadget and the version of the MIUI or HyperOS firmware. We will cover all possible scenarios, from a simple reboot to more complex manipulations with the engineering menu. If you are experiencing this for the first time, follow the instructions below carefully.
Causes of activation error
The appearance of the “Sim card not activated” on Xiaomi is often associated with desynchronization of data between the communication module and the software shell. This can occur after a failed system update, resetting to factory settings or even after a simple replacement. SIM-The system simply forgets to register the module on the network again.
Another common cause is physical contact. SIM-The card may have oxidized, or the card itself may have been damaged on the chip. SIM-maps that worked in the era 2G/3G, It can be incorrectly defined by modern modules. 4G/LTE.
The most serious cause is the IMEI, which is a unique identifier that is written into the memory of the phone in the factory. If the settings in the IMEI column are "Null" or dashing, then the NVRAM partition is damaged. In this case, the phone cannot physically connect to the network, since it does not exist for the operator.
⚠️ Warning: If you recently searched your phone or obtained a Root license, you may be at risk of partition damage. NVRAM The activation error in this case is a direct consequence of the interference with system files.
Sometimes the problem is with the carrier, if you're moving to another region or using a corporate network. SIM-card, there may be restrictions on online registration. Check if your card is working on another phone to rule out this factor.
Checking the physical condition of the SIM and tray
Before you go into deep settings, you need to rule out the trivial physical reasons. SIM-Take a close look at the gold contacts on the map, and they should be free of scratches, oxides or contamination.
Wipe the chip with a soft dry cloth, and if the card is very old and hand-cut from a larger size, it may not fit tightly with the contacts inside the tray, in which case you should contact the operator's salon for a free replacement with a new one with 4G support.
Make sure you insert the tray with the correct side. On some Xiaomi models, the tray is beveled, and trying to insert it "with force" can cause the reader to break. Also check if there is any dust or pile inside the slot.
☑️ Diagnostics SIM-map
If you have two slots in your device, try moving the card from the first to the second. Sometimes one of the readers can work unstable, and such a simple manipulation allows you to temporarily solve the problem.
Basic network settings and reboot
Often, the problem is solved by simply restarting the device, which resets the temporary errors of the communication module. Press the power button and select Reboot. If that doesn't work, try switching the network mode.
Go to the Settings menu → SIM-Select the problematic SIM card and find the "Network Type" option. Try switching from "Preferred" LTE» Only" 3G» or "Only" 2G», And then you put it back in. It will force the module to re-register.
It's also worth checking if the In-Air mode is on, and sometimes the system sticks in that state. 10-15 And then turn it off. The network indicators should start blinking, trying to find the signal.
| Action. | Where to find out. | Efficiency |
|---|---|---|
| Reboot. | Power button | Tall. |
| Flight mode | Notification curtain | Medium |
| Change of network type | SIM settings | Tall. |
| APN reset | Access point settings | Medium |
Don't forget to check the settings of the APN hotspot. On the mobile network menu, find "APNs" and hit the reset button or create a new point with your operator's settings. Misguided APN settings often block data transmission even when voice communication is working.
Resetting settings to factory
If a software failure is deeper than it seems, a complete reset may be required.This method deletes all user data, so be sure to back up your contacts and photos to the Xiaomi Cloud or your computer.
Go to Settings. → The phone. → Setting reset. Select "Erase all data." Once you reboot, the phone will look like new. SIM-If the error "Sim card not activated" disappeared, then the problem was a conflict of programs or viruses.
It is important to note that resetting does not always help if the modem system files are damaged, in which case the error will return immediately after the initial setup. If the problem persists after reset, move to more complex diagnostic methods.
⚠️ Warning: Before reset, make sure the battery is at least 60% charged. Interrupting the reset process due to battery discharge can cause the device to be completely inoperable (brick).
Sometimes it helps to delete the profiles of operators. SIM-Find the list of operators and delete all saved profiles except the current one.
IMEI check and engineering menu
The most important stage of diagnosis is the IMEI check. Dial the code *#06# in the phone. If nothing appears on the screen or you see zeros instead of numbers, then the IMEI has gone off. Without this code, the activation of the SIM card is impossible.
To do a deeper check, you can use the engineering menu. Enter the code ##4636##. Select Phone Information. Here you can see the network status and try to run the modem test. If the IMEI fields are empty, you will need to flash or restore through special utilities on your PC.
What if IMEI is zero?
In some cases, manual IMEI input helps if it is saved on a sticker under the battery (for older models) or on the box. However, in modern Xiaomi with a non-removable battery, this is done only through service software.
Try resetting network settings via the menu. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile network and Bluetooth. This won’t delete your files, but will return all network settings to factory values.
Firmware and system repair
If the software methods are powerless, the firmware itself may be damaged. You will need a computer and the official Mi Flash Tool or Xiaomi utility. ADB/Fastboot Download the current version of the firmware for your model from the official website.
The Clean Install process will completely replace the system partition, which is guaranteed to eliminate errors in the modem files, but it requires unlocking the bootloader, which can take 7 days (168 hours) after submitting an application in the Mi Unlock application.
If you are not sure of your abilities, it is better to contact an authorized service center. Self-firmware carries the risk of final failure of the device if you interrupt the process or choose the wrong version of the software.
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Use only the original. USB-cable USB 2.0 I'm using a computer with firmware. USB 3.0/3.1 Sometimes cause data transmission errors during system recovery.
Once the firmware is successfully flashed, the phone will undergo initial setup, the activation error should disappear if the problem was software, and if the SIM does not activate after a clean firmware, there is a high probability of hardware malfunction.
Hardware malfunctions of the communication module
When all software methods are exhausted, there is a variant of iron breakdown. The communication module (modem) can fail due to a fall, moisture or a voltage surge when charging with a non-original power supply unit.
In such cases, a diagnostic is required in the service, the wizard will check the voltage on the contacts of the tray. SIM And the integrity of the antenna plumes, and often the problem is solved by replacing the bottom plume with the charging connector, because that's where the contacts are. SIM-map.
It's also worth checking the antenna module. If the antenna cable has moved away from the board, the phone will see the SIM, but will not be able to find the network, giving an activation error or "No network." It is not recommended to climb inside the phone yourself so as not to damage other components.
⚠️ Warning: If the phone fell into the water, even if it dried, contact oxidation can take months. SIM It may occur after contact with moisture.
In rare cases, the power controller itself is defective, which does not apply the necessary voltage to the SIM card, which is a complex soldering that requires professional equipment.
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If you have a full flash and check on another phone SIM-The card is not working, the problem is 90% hardware and requires a visit to the service.