The modern smartphone has long ceased to be just a means of communication, turning into a digital passport, a banking terminal and a repository of confidential information. POCO The importance of basic protection is often underestimated. SIM-The card relies solely on a pattern lock or a fingerprint to unlock the screen, but if an attacker pulls your SIM card and inserts it into another phone, they will have full access to the calls and the phone will be used to unlock the screen. SMS-Messages used to confirm banking transactions.
Activating a PIN request when a device is turned on creates an additional, independent layer of security, even if the phone is stolen when it is turned off or if it is not used. SIM-The card will be moved to another device, and without knowing the four-digit code, it will be impossible to use the number, a critical measure that is often ignored by users because of a misconception about the complexity of the setup or the fear of forgetting the password.
In this guide, we will explain in detail how to install, change and unlock the security code on the MIUI and HyperOS interface. You will learn exactly where the desired settings are hidden, how to avoid blocking the card after three wrong attempts, and what to do if you still forgot the password set. The security of your data begins with simple steps that will take only a couple of minutes.
Why protection is needed SIM-maps on Xiaomi
Many users mistakenly believe that locking the screen of their smartphone completely protects their SIM card. This is not true. If the device is turned off or in flight mode, an attacker can remove the communication module and install it in his phone, at which point all incoming calls and, most dangerously, SMS with confirmation codes from banks will arrive at the criminal's device.
The PIN request function is tied directly to the SIM card chip, not the phone’s operating system. This means that protection works regardless of which device the card is inserted into, whether it’s an old button phone, an iPhone or a new Xiaomi flagship. Without entering the correct code, the network simply won’t register the device, making the SIM card useless for calls and mobile Internet.
In addition to theft protection, setting a password is useful in situations where you give the phone to children for games or friends to show photos. Even with a locked screen, some applications or functions may be available, but installing a SIM card on another device without your knowledge will be prevented at the system level.
⚠️ Note: The default default PIN is often listed on the plastic card you received when you purchased the SIM card.If you haven't changed it before, try the values of 0000, 1111 or 1234, but it's better to find the original package.
Search for security settings in MIUI and HyperOS
Xiaomi’s shell interface may vary depending on the Android version and regional firmware. SIM security settings are usually hidden deep in the system menu to prevent them from being accidentally changed. In newer versions of HyperOS, the logic of the location of the items may have changed compared to the classic MIUI.
To access the desired section, you need to open the main settings menu and find the item associated with passwords or security. Depending on the version of the software, the path can look different. SIM-maps on the home screen settings, as this option relates to device protection, not network settings.
If you can't find the right item, search inside the settings, type in a "SIM" or "PIN" and the system will suggest you go to the desired menu, which is the fastest way to navigate, especially on devices with a lot of installed applications and confusing menu structure.
Below is a table that helps you navigate the menu paths for different firmware versions:
| Shell version | The main path | An alternative path |
|---|---|---|
| MIUI 12-14 | Passwords and security → Privacy → SIM-cards | Settings → SIM-maps and mobile networks → Choose. SIM → Lockdown SIM |
| HyperOS | Passwords and security → Privacy → SIM-cards | Search in settings: "Blocking" |
| MIUI Global | Settings → Passwords & security → Privacy → SIM cards | Settings → SIM cards & mobile networks |
| MIUI China | Passwords and security → Special features | Through settings search |
It is important to note that in dual-symbol devices, the settings for each card can be managed separately, you can set different passwords for SIM card 1 and SIM card 2, which adds an additional level of flexibility if, for example, one card is used only for the Internet and the other for important calls.
Step-by-step: how to enable PIN code request
The process of activating protection is simple, but requires careful input. Before you start, make sure you remember the current PIN if it has already been installed before. If you install protection for the first time, you will need a standard code from the operator, which is often 0000 or 1111.
Follow the action algorithm to activate the function without errors:
- 📱 Open the Settings app on the home screen or in the notification curtain.
- 🔒 Go to the Passwords and Security section (or just Passwords).
- 🛡️ Select the Privacy item and then find the subsection SIM-map.
- 🔢 Click on the switch next to the desired SIM card to activate the PIN Request function.
- 🔑 Enter the current PIN (default 0000 or 1111) and press OK.
Once you've entered it successfully, the system will confirm activation, and from that point on, every time you reboot your phone or retrieve the card, you'll need to enter a four-digit code, and if you type the wrong code three times in a row, the SIM card will be locked, and you'll need to have it locked. PUK-unlocker.
☑️ Check before activation of protection
What to do if the menu item is inactive?
Changing the PIN code to a more complex one
Using standard factory passwords like 0000 or 1234 is a poor security practice. Anyone familiar with the basic phone settings can try to guess these combinations. It is recommended that immediately after activating the protection, change the code to a unique one that only you know.
To change the code, go to the same password and security menu. → Confidentiality → SIM-Select Change PIN. The system will ask you to enter the current code, then enter the new code twice. Choose a combination that is easy for you to remember, but difficult for outsiders to guess. Avoid birth dates or consecutive digits.
Write the new code in a safe place, such as a password manager or a notebook that is stored at home. Forgetting your own PIN will lead to the need to use it. PUK-Remember that a PIN code can only consist of numbers and is usually 4 to 8 characters long.
⚠️ Warning: Never store a recorded PIN in a phone case or in smartphone notes without additional protection. If the phone is stolen, the attacker will receive both the device and the key to the SIM card.
Unlocking and working with PUK-code
If you enter the PIN incorrectly three times, the SIM card will be blocked and the phone will request PUK-Personal Unblocking Key is an eight-digit code that serves as an emergency key to reset a PIN, PUK Only 10 attempts are given to enter.
Where to find out. PUK-code:
- 📄 On a plastic card-holder, which came complete with a SIM card (often hidden under a protective layer).
- 💻 In the personal account of the subscriber on the website of your mobile operator.
- 📞 Calling the operator’s support service from another number (passport data must be called).
The unlocking process is simple: enter PUK-The code, then the system will ask you to come up with a new PIN and confirm it, and then the network will be restored. PUK-The code will lead to a complete and irreversible locking of the SIM card. It will be impossible to restore it, you will have to get a new SIM card with a number in the communication salon.
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Save it. PUK-code in the cloud storage or send yourself to a secure messenger immediately after receiving the SIM card, this will save you in a situation where the plastic card holder has long been lost.
Frequent problems and ways to solve them
Xiaomi users may encounter a number of typical problems when setting up protection, such as a phone that can constantly request a PIN every time it exits flight mode, even if the "Request on" feature is turned off, which may be caused by a failure in the communication module or SIM card contacts.
In some cases, after updating the firmware, the security settings may reset or become unavailable. If you see an error message saying "Failed to change the PIN code", try to remove the SIM card, wipe the contacts and paste back, and temporarily disabling the second SIM card, if there are two of them, also helps.
Another common situation is that the phone says "SIM card locked" even though you're confident in the code, which could mean that the card was blocked by the operator due to suspicious activity or debts, and the PIN request has nothing to do with it, in which case you should contact the technical support of your carrier.
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If the phone stopped seeing the SIM card from the last attempts to enter the code, don't panic. Do a complete reboot of the device. In rare cases, resetting the network settings helps, but this will delete the saved Wi-Fi passwords.