A modern smartphone stores not only contacts and photos, but also access to banking applications, messengers and social media accounts. SIM card is a key element of this ecosystem, as it is the phone number that is often used to authenticate two-factor and restore access to important services. Owners of Xiaomi, Redmi and Poco devices often wonder about improving security, unaware that standard lock screen protection does not save the SIM card from being moved to another phone.
If an attacker takes possession of your device or simply removes the communication module and inserts it into his gadget, he will be able to receive the message. SMS-This opens the way to your financial resources and personal correspondence. PIN-The code on the SIM card itself creates an additional operating system-independent barrier. Even if the phone is turned off or reset to factory settings, without this code, the communication module will not work.
In this article, we will discuss how to activate the protection. SIM-shell-card MIUI We'll look at the algorithm of actions, we'll look at possible input errors and explain what to do if you forget your password. PIN-The code for most operators is 0000 or 1234, but you can’t rely on these values after activating the protection.
Why do you need protection? SIM-maps in Xiaomi smartphones
Many users mistakenly believe that the password on the lock screen is enough for complete security, but the protection of the operating system and the protection of the communication module are two different levels. PIN-It can be moved to any other device and receive incoming calls or SMS-This is a critical vulnerability in the age of mobile banking.
SIM card passwords in Xiaomi ensure that your number is isolated from other devices. When you turn on your phone or remove your SIM card, the system will always ask for the code. Without it, the communication module remains locked, making it impossible to use the number for calls or authorization in applications, which is especially important in the case of a device theft.
In addition, the availability PIN-This code prevents the inadvertent use of paid services if children use the phone, and they may not know the code and may not be able to make a call or send a message requiring confirmation. Security is achieved by sharing access to the phone interface and access to the operator’s network functions.
⚠️ Warning: Never set too simple combinations, such as 1111 or birth dates, that are easy to guess. Use unique combinations of numbers that you can remember but that are not obvious to outsiders.
It is important to understand the difference between the screen unlock code and PIN-The first one is stored in the phone's memory and resets when it's completely flashed or reset to factory settings. The second one is written directly to the SIM card chip and stored even when it's moved to another device. + SIM card is the gold standard of security.
Preparation for password installation: important nuances
Before you start changing the security settings in the menu MIUI, You need to make sure you're ready for the procedure. PIN-If you haven't changed factory settings before, it's probably the default code, Tele2) These values may vary, but most often it is 0000 or 1234.
It is very important to have on hand. PUK-This is a special unlock key that you need if you type three times incorrectly. PIN-code. PUK-The code is usually shown on a plastic card-based card that came with a SIM card, or is available in the operator's personal account. PUK-code after three input errors PIN-The card is blocked forever, and it will have to be changed in the communication salon.
- 📱 Make sure the SIM card is properly installed in the tray and is determined by the phone.
- 🔢 Find it. PUK-code in the contract with the operator or the application "My MTS" / "My Beeline».
- 🔋 Charge your smartphone to a minimum 20-30%, So that it does not turn off during the setup process.
- 📶 Check for network signal, although password setting is possible without active connection.
If you use a two-sim smartphone Xiaomi, the procedure will need to be repeated for each SIM card separately, the security settings apply individually to each slot, and do not ignore the protection of the second card, especially if it is also tied to bank accounts or used for work.
☑️ Checking before setting a password
It is worth noting that the interface settings may vary slightly depending on the version of the shell HyperOS or MIUI 12/13/14. However, the logic of the security system remains the same for all models, whether it is the flagship Xiaomi 14 or the budget Redmi Note.
Step-by-step instruction: installation PIN-Xiaomi code
The process of activating the SIM card protection in Xiaomi smartphones is quite simple and takes no more than a minute. All the necessary settings are in the standard system settings menu. You do not need to install third-party applications or have root rights.
First, open the Settings app on the home screen or in the notification curtain. In the settings list, find a section that could be called Passwords & Security or simply Security. In some firmware versions, the desired item is in the About Phone section» -> «Settings SIM-We need to get into the SIM control menu.
Select the SIM card you want to set your password to (SIM 1 SIM In the menu that opens, find the "Protection" switch. SIM-cards” or “Blocking SIM-Activate it. The system will immediately request the current input. PIN-If you change factory settings, type 0000 or 1234.
Settings → Passwords and security → Privacy → SIM-card protectionOnce you've successfully entered the old code, the system will suggest you come up with a new one, enter the 4-8 digit combination you want, and confirm it with re-entry, the new password will be effective immediately, and every time you reboot your phone or retrieve your SIM card, you'll need to enter that particular code.
If you entered the wrong code, the system will warn you of the error and show you how many attempts are left. PUK-Make sure your fingers don't shake and the screen is clean to avoid accidental pressing.
How to change or disable the password on the SIM card
There are different situations: you may have forgotten a complex password, decided to simplify access, or, conversely, you want to strengthen the protection by changing the code to a more complex one. In any case, the procedure for changing or disabling the password goes through the same settings menu in Xiaomi, the main condition is that you must know the current valid code.
To change the password, go to the “Protection” menu. SIM-map where the lock switch is located, next to or below it should be the option "Change" PIN-code” or “Replace PIN». Click on it. The system will ask you to enter your current password, and then double-new.
If your goal is to completely disable your password request when you turn on your phone, the process is similar to installing. SIM-"s" is active and press it to deactivate. PIN-The SIM card will then be unlocked for use without further questions.
| Action. | Required code | The result |
|---|---|---|
| Incorporation of protection | Current PIN (or 0000) | Requesting code when starting the phone |
| Change of password | Current PIN | New access code installed |
| Disabling protection | Current PIN | SIM card works without password |
| Unlocking (3 errors) | PUK-code | Resetting PIN and the ability to set a new |
It is not recommended to change passwords to easily memorized ones often if the phone falls into the hands of different people (for example, in the family); it is better to install a reliable code once and remember it than to constantly simplify protection. Security often requires small sacrifices in the form of convenience.
What to do if the settings menu does not open?
Remember that disabling your password makes your SIM card vulnerable. If you decide to sell your phone, be sure to remove the SIM card or make sure it doesn't store important information, although contacts are better kept in the Google cloud or Mi Account.
Unlocking the SIM card: PUK-code and recovery
The most critical situation a user may face is blocking the SIM card after three incorrect inputs. PIN-The screen of the Xiaomi smartphone in this case will inform that the SIM card is blocked, and will require input PUK-Personal Unblocking Key: Don't panic, but you need to be careful.
PUK-A code is a master key that resets the error counter. PIN-It's 8 digits, unlike the code. PIN-code that you create yourself, PUK It's issued by the carrier, and it's unique to each SIM card, and you can only enter it incorrectly 10 times. After the tenth error, the SIM card is permanently blocked and you can't restore it, you have to buy a new one.
⚠️ Attention: Never enter PUK-If you're not sure about the numbers, you should first look up the exact information from the operator. Ten attempts is very small, the risk of losing the number is high.
Where to find out. PUK-code:
- 📄 On a plastic card to which the SIM card was attached when you bought it (usually hidden by a protective layer).
- 🌐 In the personal account of the subscriber on the website of the operator.
- 📱 In your operator’s mobile application (Site “Profile” or “Settings»).
- 📞 Calling the operator’s support service from another number (you need to call passport data).
For input PUK-Just dial 8 digits on a locked Xiaomi screen. The system automatically unlocks the SIM card and immediately prompts you to come up with a new one. PIN-Enter the new code. PIN, If you confirm it, the SIM card will be ready to go again. PIN-code-reset.
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Save it. PUK-code in a safe place (for example, in a password manager or write it in a notebook), but do not store it with your phone.
If the SIM card is permanently blocked (the limit of PUK attempts is exceeded), only the replacement of the SIM card in the operator's cabin will help. The phone number is usually saved, but the plastic card with the chip changes, it is free or paid service depending on the conditions of your tariff.
Frequent problems and ways to solve them
Despite the simplicity of the procedure, Xiaomi smartphone users may face a number of technical problems, often not related to a device breakdown, but to the peculiarities of old SIM cards or software conflicts, and understanding the reasons will help avoid unnecessary trips to the service center.
One of the common problems is that the phone is constantly asking for PIN-This can happen if the SIM card has physical damage to the contacts or if it is very old and its chip is unstable. MIUI.
What to do in such cases:
- 🔄 Reboot your smartphone. Sometimes it resets the temporary glut of the communications module.
- 🧹 Wipe the SIM card contacts with a soft eraser or an alcohol napkin.
- 📲 Try inserting the SIM card into another phone to rule out the breakdown of the smartphone itself.
- 🛠 Update the SIM card from the operator if it is used more 5-7 years.
Another situation is the button “Protection” SIM-The card is inactive (gray) or has disappeared from the menu, which may mean that the SIM card is not defined by the system, or is currently searching for the network. Wait for the signal icons to appear in the status bar. If the problem persists, check if the phone is in Flight mode».
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If the SIM card constantly requires code or is not accepted by the phone, 90% of the time the problem is physical wear and tear on the card chip, not Xiaomi software.
In rare cases, security settings may reset after a system update. Check the security status again. It is also worth considering that some corporate SIM cards or virtual carrier cards may have their own restrictions on changing the security status. PIN-remotely.
Additional security measures in MIUI and HyperOS
Setting a password on a SIM card is just one step in protecting your Xiaomi device. The company’s ecosystem offers many other tools that combine to create a strong shield against intruders, ignoring these features negates efforts to protect the SIM card.
First of all, look at the device search feature, which allows you to remotely lock your phone, erase data, or locate it in the event of a theft, and it's tied to Mi Account and has to be activated by every owner, without which the phone becomes a brick for the owner, but remains accessible to thieves if they reset.
It's also recommended to use biometric protection. A fingerprint scanner or facial unlock in Xiaomi works quickly and conveniently. However, remember: biometrics is convenient, but less reliable legally and technically than a complex digital password. Biometrics can be forged (in theory), and password is the knowledge that only you have.
And remember, Second Space or Guest Mode, which allows you to create an isolated environment in your phone for other users, and in this space you can hide certain apps, photos and contacts, which is useful if you give the phone to a child or colleague, but you don't want them to see your personal information or use your linked cards.
⚠️ Attention: Check the list of devices that have access to your Google and Mi Account regularly. If you see an unfamiliar device, change your password immediately and end your session.
A comprehensive approach to security includes not only technical settings, but also digital hygiene: Do not install applications from unknown sources, avoid connecting to open Wi-Fi networks without a VPN, and do not follow suspicious links to SMS. A password SIM card is a powerful milestone, but it is powerless if you hand over access to the phone to scammers yourself.