The protection of personal information in a modern smartphone goes far beyond a simple screen locker or fingerprint scanner. SIM-The card is a fundamental level of security that is often ignored by users, although it is this that prevents unauthorized access to your calls and calls. SMS-Messages when retrieving the communication module: owners of Xiaomi brand devices and Redmi sub-brand, working on the shell MIUI, You may encounter nuances of settings location that are different from stock Android.
Activating this feature becomes critical in situations of loss of a gadget or theft, where an attacker can try to move your SIM to another phone to obtain confirmation codes from banking applications. Turning on a PIN code blocks the SIM card from working even on a third-party device without entering a secret combination of numbers, which makes the theft not only unpleasant, but also technically useless for a thief in terms of accessing your accounts.
In this article, we will take a look at the algorithms for activating protection, look at the differences between interface versions, and answer questions related to access restoration. You will learn how to manage security parameters through the system menu and understand the difference between device access codes and the communication module.
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Password setting SIM-Your card protects yours. SMS And calls even if the phone is stolen and the SIM card is retrieved.
Why protection is needed SIM-password-card
Many users mistakenly believe that locking the screen of a Pattern or Face ID smartphone completely solves the security problem, but this is a misconception, since when the phone is turned off or the SIM card is removed, the screen protection ceases to act on the communication module.
The main purpose of setting a password is to prevent third parties from using your number, and if a scammer takes possession of your phone, they will not be able to use your SIM card to make calls or, more importantly, to receive your phone. SMS-Banking applications and instant messengers often use this code. SMS to log in to your account, so protecting your room is equivalent to protecting your finances.
The MIUI interface provides a handy tool to manage these settings, allowing not only to install the code, but also to change it or disable the function if necessary. It is important to understand that the standard factory password is often simple (for example, 0000 or 1234), so replacing it with a unique combination is a must for every Xiaomi owner.
- 🔒 Blocking access to voice mail and incoming calls without authorization.
- 💰 Protect against unauthorized paid subscriptions through your number.
- 📱 Keeping contacts if they are stored on a SIM card rather than in the cloud.
Preparation for PIN code installation on Redmi
Before you start changing your security settings, you need to make sure you have all the data you need on hand. PUK-This code is required solely to unlock the SIM card if you mistype the PIN three times. PUK-The SIM card will be permanently blocked, and it can be restored only by the operator.
Find it. PUK-The code can be found on a plastic card that was issued with the SIM card when you bought it, or in your mobile operator’s personal account on the official website, and this data is often available through a support chatbot or hotline. Write this code in a safe place before changing the settings, as Xiaomi’s system does not store it in the open after installing the protection.
Make sure your Redmi battery is at least 20-30% charge, although the setup process doesn’t require much power, suddenly turning the device off while writing data to the SIM chip can cause software failure.It’s also recommended to have an alternative way of communicating on hand in case you accidentally block the main SIM.
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Save it. PUK-code in notes or take a photo of a plastic converter card, since without it it it is impossible to restore access to the SIM card.
Step-by-step: activation of protection in MIUI
The process of turning on protection may vary slightly depending on the version of the MIUI shell (12, 13, 14 or HyperOS), but the logic of the menu remains the same. You need to go to the settings section responsible for passwords and security. Open the Settings app on the home screen or in the notification curtain.
Follow the path: Passwords and security → Confidentiality → System Security (in some versions, protection is immediate) SIM-In the menu that opens, you'll see a list of all SIM cards installed. Select the one you want to set the protection on and switch the switch to active position.
The system will request the current PIN, which is the default for new SIM cards, which is often 0000 or 1234, but it's better to check with the operator. Once you've entered it, the system will suggest you come up with a new code and confirm it, and that code will now be requested every time you reboot your phone.
☑️ Checklist for PIN activation
Once installed successfully, the system will notify you that the protection is activated. From now on, every time you turn on or restart a Xiaomi smartphone, a system window will appear requesting a PIN code before you unlock the desktop, which ensures that without your knowledge, the SIM card will not be registered anywhere.
What to do if the menu does not open?
Code management and password change
In the same menu where you turned on the protection, there are functions available to change your current password or completely disable a request. If you decide to change the code, the system will first ask you to enter the current valid PIN, and then twice new.
To turn off the function, simply put the switch in an inactive state, you will need to re-enter the current PIN to confirm the operation, a useful feature if you plan to temporarily give the phone to a child or another person and do not want to be bothered by constant password requests when rebooting.
Usually, three attempts are given, and after the third erroneous attempt, the SIM card is blocked and requires input. PUK-If and when PUK-code entered incorrectly 10 times (in some cases 5), the SIM card is permanently blocked and requires replacement from the operator.
| Parameter | Description | Where to find out. |
|---|---|---|
| PIN code (PIN) | Daily Password for Accessing the Network | Settings → Passwords and security |
| PUK-code | Unlock code after PIN errors | SIM card converter, Personal Account |
| PIN2 (PIN2) | For special functions (fixed set, tariffification) | I also rarely use it. |
| PUK2 | Unlocking PIN2 | The mobile operator |
Common mistakes and ways to solve them
One of the most common problems is that the user does not know the standard factory password, and in this case, you should not guess the pumpkin method.
⚠️ Warning: Three incorrect PIN attempts will result in SIM card blocking and request PUK-Don't experiment with codes unless you're sure of them!
Another common mistake is the confusion between the unlock code and the SIM code, which is different security systems, so if a phone asks for a PIN right after you turn it on, before the desktop comes on, it's a request from a SIM card, if after you load the icons, it's a device protection, and if you put a Wi-Fi password or a Google account in here, it won't help.
Sometimes users accidentally activate Fixed Number Dial (FDN) which requires PIN2, which causes the phone to stop calling any numbers other than those listed, and to turn off this feature in the same menu, select "Disable FDN" and enter PIN2 (usually listed on the operator's map).
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Don’t confuse the SIM PIN with the graphical screen key – these are different levels of protection requested at different times.
What to do if the SIM card is blocked
If you are still faced with the screen, enter PUK-"code," don't panic. Enter the code you saved in advance. Once you've entered it, the system will ask you to come up with a new PIN. Enter it twice to confirm.
In a situation where PUK-The code is unknown or lost, the only way out is to contact the operator's salon or call the support service from another number, you will need to confirm your identity by answering security questions or naming passport information. PUK-code.
There are Android apps that supposedly can unlock the SIM card, but in the case of modern chips, it's a myth. PUK-It is impossible to restore access by software methods, since protection is built into the hardware level of the chip.