Xiaomi, Redmi and Poco smartphone owners often face an annoying notification saying “failed to activate” SIM-This problem is especially relevant for global versions of firmware that are trying to communicate with activation servers in China. The situation is aggravated when the device stops seeing the network even when there is coverage, and the battery is discharged due to constant attempts to register.
In this article, we will discuss the technical causes of the SIM activation error and provide step-by-step instructions for fixing it, learn how to safely disable system services that interfere with the communication module, and which MIUI or HyperOS settings require special attention.
There are several proven ways to solve the problem, from simple actions in the settings menu to the use of the engineering menu, and it is important to understand that in some cases the error is not due to a phone breakdown, but to malfunction of the operator or regional restrictions. Let's look at each aspect in detail.
Causes of activation error SIM-map
The main reason lies in the mechanism of protection against theft, built into the shell. MIUI. With each reboot or retrieval of the card, the system tries to send a hidden message. SMS-requesting Xiaomi servers to verify the legitimacy of the device: If the server is not available or the SIM card balance does not allow you to send a message, there is a cycle of errors.
Another factor is regional confluence: Global firmware versions often have a China-sewn region, which forces the phone to search for local towers and services that are physically inaccessible in your country, leading to a situation where the network status is constantly changing from "Emergency Calls Only" to "Network Search."
⚠️ Attention: Constant activation attempts can quickly drain the battery and put a strain on the processor, causing the housing to heat up in the upper end of the smartphone.
And there's also a physical cause, and the contacts in the tray could have oxidized, by themselves. SIM-card - to get damaged or have an old cut-SIM format that sits loosely in the combined tray, sometimes the problem is solved by replacing the card from the operator with a new one with support 4G/LTE.
Basic settings of the network and region
The first thing to do before using complex methods is to check the basic settings. Often users accidentally change the region or network type, which blocks the normal operation of the module. Go to the Settings menu → Advanced Settings → Region and make sure that your country or the “Russia” option is selected.
Next, check the type of preferred network. → SIM-maps and mobile networks → Network type Select mode Preferably LTE. If your carrier does not support VoLTE in your region, try switching to the mobile phone. 3G (WCDMA) To check for a signal, to see if it's blocked. LTE-module.
☑️ Checking basic settings
Make sure you check if the flight mode is on by accident, and make sure you do it yourself. SIM-If it's working, it's a software problem. If it's not, you can contact the operator's office to replace it.
Disconnecting the Mi Sim Activator
The most effective software method is to disable the system application that is responsible for activation. It is the Mi Sim Activator component that generates the "failed to activate" error, which runs in the background and requires constant access to the network.
To get to it, go to Settings → Apps → All Apps. In the upper right corner, click on three dots and select “Show System Processes.” In the list, find the Mi Sim Activator (or SIM Activation Service) app. Click on it and select “Disable”.
If the Disable button is inactive, try first hitting Stop and then Disable.In some versions of HyperOS, you may need to remove updates to this component through a three-dot menu within the app.
⚠️ Warning: After the service is disabled, the error notification will disappear, but the theft protection feature associated with the binding SIM, Make sure you have a strong lock password.
What to do if the button to turn off gray?
Resetting APN and Network Settings
Incorrect access points (APN) And it can interfere not only with the Internet, but also with the registration process on the network, and resetting these settings returns the parameters to factory values, eliminating configuration conflicts. → SIM-maps and mobile networks → (Choose. SIM) → Access points (APN).
At the bottom of the screen, click Reset or Reset to default settings. The phone will then reset the operator profile, which is safe and does not delete your personal data, contacts or photos.
Aside from APN, there is a full network reset, which is in the Settings menu → Connection & Sharing → Reset Wi-Fi, mobile networks and Bluetooth. This step is especially useful if you have recently changed carriers or moved to another region.
| Parameter | Before dumping. | After discharge | Influence on error |
|---|---|---|---|
| APN access points | User/Errorful | Factory operator | High. |
| Bluetooth settings | Associated devices | List empty. | Low. |
| Wi-Fi settings | Preserved networks | List empty. | Average. |
| Mobile network | Traffic limits | Dropped. | Average. |
Using an engineering menu to select a network
For advanced users, a hidden interface is available to the engineering menu, which allows you to force the type of network to be selected, which helps if the phone is stuck in 4G search where only 2G is available. Open the Phone app and type ##4636##.
In the menu that opens, select Phone Information. Find "Install preferred network type." Try changing the value to LTE Only (LTE only) or NR/LTE/GSM. If you lose your signal after selecting LTE Only, you don't have 4G coverage in your area and you need to return the setting to Auto mode.
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If the ##4636### code doesn’t work on your Android version, install the Activity Launcher app from Google Play. Search for Testing and run Testing activity, which will open the same menu.
Be careful when choosing LTE Only, which is a mode where incoming calls may not pass unless VoLTE technology is configured, and use this mode temporarily to check the stability of the connection.
Problems with global firmware and CN-version
Owners of smartphones bought on AliExpress or imported from China often face the problem of “China global”: in such devices, the region is software changed, but the system files contain links to Chinese activation servers, which causes constant search of the device and SIM errors.
The solution might be to flash to a clean global version (Global Stable) through a computer with an unlocked bootloader, but it's a complex process that requires skill, and a simpler, less reliable way is to use regional patches or install GPS emulation apps to trick the system into thinking the phone is in China.
⚠️ Warning: Unlocking the bootloader will void the warranty and may result in data loss.If you are not sure about your actions, contact the service center.
There is also a method of disabling the activation service through ADB-So, you can connect your phone to your PC, you can set up debugging. USB And put in a command:
adb shell pm disable-user --user 0 com.miui.simactivationThis command forcibly disables the activation pack without the need for root rights. To get it back, use the command to replace the disable-user with enable.
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The fastest solution for most users is to disable the Mi Sim Activator app in the application settings, which eliminates the error 90% of the time without losing warranty.