Owners of budget smartphones like the Xiaomi Redmi 9 often face intrusive system requests after resetting or updating the firmware.One of the most annoying moments is the constant appearance of the selection window. SIM-card or pin code request even when the device has already installed an active communication module. MIUI, The device, which is based on the operating system of the phone, has its own peculiarities of working with the priorities of networks, which sometimes leads to software conflicts. The user can observe a situation where the device endlessly offers to choose a card for calls or the Internet, interrupting the work of other applications.
The problem is often not a physical breakdown, but a software failure or incorrect default settings. The system may “forget” your choice or consider your current configuration invalid. The SIM selection menu appears because the smartphone cannot automatically determine the priority device for voice or data transmission at the current time. This is especially true for two-symbol models, where the switching logic sometimes fails after a security update.
In this article, we will detail how to force settings and remove unnecessary notifications. You will learn how to manage network priorities, block unnecessary slots and reset modem settings. Redmi 9 has a flexible settings system that, when approached correctly, will allow you to forget about constant pop-ups. We will look at both standard methods through the interface and deeper settings of the engineering menu.
Reasons for the request for selection SIM-map
Before we take active action to fix the problem, we need to understand the root of the problem: System failure is the most common reason when the phone's software stops reading the slots correctly, and this can happen after a failed firmware update, a sudden power outage, or installing incompatible software from third-party sources.
Another reason is physical contact or lack thereof: If the SIM card is removed but the settings do not indicate that the slot is empty, the system will continue to poll the contact. Priority conflict arises when the user has not previously selected the main card for calls, and each time important MIUI services are launched, you need to clarify.
⚠️ Attention: Frequent requests may indicate an attempt to access unauthorized information. SIM-to the malware manager, although on modern versions of Android it is rare.
Sometimes the problem is temporary and involves overloading the communication module, if you just turned on your phone or left the safe reception zone, the registration process on the network can take longer than the timeout allocated by the system, as a result, the user sees the selection menu, although in a minute the situation could normalize itself.
Setting priorities SIM-card MIUI
The most effective way to remove the permanent menu is to rigidly fix system preferences. You need to go to the settings and manually specify which slot is the main one. → SIM-Maps and mobile networks. This shows all the maps installed and their current status.
In the "Default" or "Call Settings" section, select a specific SIM-You don't leave the "Always Ask" value, because that's what causes the intrusive window to appear, and you fix the system's choice that it doesn't have to make decisions for you anymore».
☑️ Setting priorities
If you only have one card inserted and the phone still asks you to choose, try switching to the second (empty) and back again.This action will overwrite the configuration preference file. Xiaomi Redmi 9 also allows you to turn off unused slots right in this menu, which completely eliminates their polling system.
After making the changes, be sure to restart the device. A restart is necessary to apply new parameters at the modem level. Without this step, the old settings can remain in the cache and continue to cause errors.
Using an engineering menu to block
For more advanced users, you can access hidden settings through an engineering menu, which allows you to control the radio module at a deeper level. To log in, open the Phone app and type in the combination ##4636##. If the code doesn't work, your firmware version may be blocking that access and you'll need to install a special activator application.
In the menu that opens, select “Phone Information.” Here you will see a list of available networks and status. SIM-Find "Set Preferred Network Type" or similar. The engineering mode allows you to force-disable voice calls or data transfers for a particular slot, which can solve the problem of constant polling.
| Parameter | Description | Recommended value |
|---|---|---|
| Radio Power | Radio switching on/off | On |
| Preferred Network | Type of network | LTE Only / GSM Only |
| Ping Test | Connection check | Run (for the test) |
| SMSC Refresh | Update of centre number | Refresh |
Be careful when changing the settings in this section. Incorrect settings can lead to a complete loss of communication, which is difficult to restore without resetting the network settings. If you are not sure about your actions, it is better to limit yourself to standard methods of setting up through the menu.
What if the code doesn't work?
Resetting network and modem settings
When the software settings are so downed that manual change doesn't help, a complete reset of network settings is required.This action won't delete your personal files, contacts or photos, but will return all Wi-Fi, Bluetooth and mobile network settings to factory values. Go to Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth.
After clicking the Reset button, the phone will restart network services.The reset process clears the modem error cache and removes conflicting APN profiles.This often helps in cases where Redmi 9 is "stuck" in the network search or SIM selection cycle.
APN access points are a key element for mobile internet operation, and cleaning them often solves network login issues.
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Save a screenshot of your APN settings before resetting. Go to your mobile network settings, select your carrier's hotspot, click three dots in the corner, and select Copy or just take a picture of the screen, which will save you time to recover.
Physical inspection and maintenance of the tray
And you can't rule out hardware, and if the software didn't work, maybe the problem is physical contact. SIM-Check the contacts on the card and inside the phone carefully, and the presence of dust, oxides or mechanical damage can cause false connection/disconnection signals.
Try to wipe the SIM card contacts with a soft wipe or an alcohol napkin. Make sure the card sits tight in the tray and doesn't hang around. Mechanical backlash can cause a brief break in the contact, which the system perceives as the card's extraction, and trigger the search and selection process again.
- 📱 Check the integrity of the plastic base of the SIM card – chips can interfere with contact.
- 🔍 Inspect the tray for bent contacts inside the smartphone.
- 🔄 Change the SIM cards in places (in slot 1 and slot 2) to exclude the breakdown of a particular connector.
- 🧹 Gently rinse the slots with compressed air to remove dust.
If the problem persists for only one particular slot after cleaning and repositioning, there is a high probability of malfunctioning of the communication module or plume itself, in which case hardware repair may be inevitable, especially if the phone fell or was exposed to moisture.
Update firmware and rollback of the system
Often menu bugs SIM-The cards are known to the developers and are patched in security updates. MIUI In the Settings section → The phone. → Version. MIUI. If an update is available, install it.The current firmware contains fixes for a variety of known bugs, including problems with the radio module.
In some cases, the problem appears after the update. If you notice that the latest version worked fine, consider rolling back on the previous stable version or waiting for a patch. However, it is characteristic of Xiaomi Redmi 9 that older versions may have vulnerabilities, so it is better to wait for the fix.
⚠️ Warning: Before updating or rolling back the firmware, be sure to make a full backup of the data.The flashing process can lead to loss of information if something goes wrong.
Sometimes, complete flashing of the device through a computer with all data clearing (Clean Install) helps, a radical method that is guaranteed to eliminate any software errors, but takes time and skill. Clean installation eliminates the impact of third-party applications and modified system files.
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Regular system updates are the best prevention of software failures associated with the operation of communication modules and the MIUI interface.