A modern smartphone stores a huge amount of confidential information, and protecting access to it becomes a priority for each owner. SIM-A card in a Xiaomi device, you create an additional, independent layer of security that blocks access to the number even when you remove the communication module and install it in another phone. SMS, accounts in messengers and personal correspondence.
The procedure for activating protection in the MIUI or HyperOS shell requires no special technical knowledge and takes only a couple of minutes. However, despite its simplicity, many users ignore this feature, relying solely on locking the screen, which is an error. In this article, we will discuss in detail how to enable a PIN request, where to find the necessary settings and what to do if you forget the set numbers.
It's worth noting that SIM security is a GSM standard that works at the level of the operator chip, not the operating system, so the settings we're going to change only tell the communication module to request code every time it's turned on, and understanding this mechanism will help avoid confusion when you reset or flash the device.
Why do you need protection? SIM-maps in Xiaomi smartphones
Main purpose of installation PIN-If an attacker takes possession of your device when it's off or simply pulls out a SIM card and inserts it into his phone, without the code, he won't be able to make calls or use the mobile Internet. This creates a robust barrier to identity theft through two-factor authentication systems.
Many services, including banking applications and social networks, use the SMS By accessing your number, a fraudster can recover passwords from all your accounts. SIM-The card guarantees that even with the full unlocking of the smartphone by an unauthorized person, the communication module itself will remain blocked until the secret code is entered.
In the event of a phone theft, an unscrupulous finder may attempt to make expensive calls or connect paid subscriptions. SIM lock will prevent any actions with the number until the correct password is entered, keeping your funds in your account.
- 🔒 Complete isolation of the room from unauthorized persons when the device is stolen.
- 🛡️ Protection of bank codes and account login confirmations.
- 🚫 Blocking the ability to make paid calls and purchases.
- 📱 Independence of protection from the state of locking the screen of the smartphone.
⚠️ Warning: Never use standard factory passwords like 0000 or 1234. Attackers know these combinations and check them first.
It's important to understand the difference between locking your screen and locking your SIM card. The screen protects access to the Android interface, but it doesn't protect the SIM itself. If you take out the communication module and paste it into another phone, all the data on it will be accessed (contacts if stored on the SIM card) or the number can be used. The SIM password solves this problem.
Where to find security settings in MIUI and HyperOS
The interface of the MIUI shell and the new HyperOS may differ depending on the Android version and the firmware region, but the logic of the settings location remains the same. You don't have to search for hidden engineering menus or use third-party applications. All the necessary tools are in the standard system settings menu.
To access the desired section, you need to go to the main settings menu and select the item related to passwords and security. In some versions of the firmware, this section may be simply called “Passwords and Security”, in others it is entered in the “Privacy” subsection.
An alternative and often faster way to get to the menu is to search by settings. At the top of the Settings screen is the search bar, and by typing in a SIM or Pin request, the system will suggest you go to the desired menu item, bypassing manual navigation through the nested folders.
- 🔍 Open “Settings” and find the “Passwords and Security” section».
- 📲 Go to the “Privacy” or “Device Security” subsection».
- 📶 Select "System Security" or "Settings" SIM».
- 🔐 Find the option “Blocking” SIM-cards" or "protection SIM».
The path to settings can vary. For example, on global firmware versions, the path often looks like this: Settings. → Passwords and security → Confidentiality → Special permits → Lockdown SIM. On Chinese versions or in HyperOS, the structure can be simplified before Setting up. → Passwords and security → Lockdown SIM-map.
Step-by-step: how to set a password on SIM
The activation process is as unified as possible and does not require complex manipulations, the main thing is to act consistently and carefully enter the requested data. Before you start, make sure that the slot has a SIM card on which you plan to put protection.
First you need to activate the password request function. SIM-You will see the switch "Blocking" SIM-Once activated, the system will ask you to enter the current PIN. By default, if you have never changed it, it is the standard combination indicated on the plastic card holder that came with the SIM card (usually 0000 or 1234).
Once the factory code is successfully entered and the switch is turned on, the system will suggest changing the PIN to your own, which is a critical step. You will need to enter the new code twice to confirm, and it is recommended to use a 4-8 digit combination that is easy to remember, but difficult to guess.
☑️ Checking before setting a password
Once the code is changed, the system may require the device to restart to apply the changes. Once turned on, the smartphone will immediately request the PIN you entered. If the input is successful and the network is on, then the protection is activated. Now, every time you turn on the phone or remove the SIM card, this code will be required.
⚠️ Note: If you enter the wrong PIN three times in a row, SIM-The card will be locked. PUK-code, which is also indicated on the plastic holder or in the operator’s personal account.
Don't neglect to check the security. Turn off the phone and turn it on again. PIN-code" or "Unlock SIM», So if the phone went straight to the desktop or the screen unlock request, it means that the SIM card itself is not protected.
What to do if you forgot PIN-code or card blocked
A forgotten password is a common occurrence, especially if the code has been changed for a long time and has not been used for a long time, and the main rule in this situation is not to panic and in any case not to try to guess the code by pumpkin. Three incorrect attempts will enter the SIM card in a lock state, after which you will need to PUK-code.
PUK (Personal Unblocking Key) is an 8-digit unlock key that is unique to each SIM card and is not changed by the user, and can be found on a plastic card that was issued when you bought a SIM card (often designated PUK or PUK1). If the card is lost, the code can be found in the operator's personal account on the website or obtained from the communication salon when you present your passport.
The process of unlocking through PUK-The code is simple: after a triple input error PIN smartphone will offer to enter PUK. Introducing it, the system will ask you to come up with a new one. PIN-The code is then restored, and it's important to write the new code right away so that the situation doesn't happen again.
| Type of code | Length | Appointment | Where to find out. |
|---|---|---|---|
| PIN | 4-8 digits | Daily unlocking of the SIM | Invents the user / Factory on the map |
| PUK | 8 digits | Unlocking after PIN errors | Plastic card, Personal Cabinet, Operator |
| PUK2 | 8 digits | PIN2 change (rarely used) | Plastic card, Operator |
| Super PUK | 10 numbers | Unlocking after blocking PUK | Only in the cabin of the operator with a passport |
There is also a code called PUK2 that is used to change PIN2. PIN2 is used to access specific functions such as limiting outgoing calls or charging. These features are rarely used in modern conditions, but if the system requests PUK2, it should also be searched for by the operator.
What happens if you exhaust PUK attempts?
Password management and additional settings
Once you have security, password management becomes part of your digital hygiene. PIN-code to a more complex or, if necessary, disable the request for a password when you turn on the phone, all these actions are performed on the same menu where the original setting was made.
To change the code, you need to select the option “Change”. PIN-code SIM-The system will ask you to enter the current code, then twice new, and it is recommended to change passwords periodically, at least once a year, especially if you suspect that someone may have seen you enter the code.
Disabling protection also requires entering the current PIN-Just switch the "Block" switch. SIM-If you turn your phone on or switch your SIM card to another device, you won't ask for a password, which is convenient if you change your phones often, but it reduces security.
- 🔄 Regular shifts PIN-The code increases the overall level of protection.
- 🚫 Disabling Password Makes SIM Card Vulnerable When Phone Theft.
- 📝 Keep it. PUK-code separate from the phone (e.g. in cloud storage).
- ⚙️ The settings are applied instantly and do not require rebooting.
It's worth mentioning the autolock feature, which is sometimes found in security settings. It allows you to automatically block. SIM-card if the phone has not been used for a certain time or if you have failed to log in.This is an optional option not available on all Xiaomi models.
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Save it. PUK-You can access the code in your notes or send it to your messenger, and you can access it from any device, even if you're not a user. SIM-The card is blocked and the Internet works only through Wi-Fi.
Frequent problems and ways to solve them
Despite the simplicity of the procedure, users may encounter a number of typical problems. It often happens that the SIM Lock menu item is inactive (shadowed in gray) and cannot be pressed, which usually means that the phone is not seeing the SIM card at the moment or it is damaged.
Another common situation is that the phone is constantly asking for PIN-This may indicate a software failure in the communication module or damage to the contacts of the SIM card itself, in which cases the removal and re-installation of the communication module, as well as wiping the contacts, helps.
If the problem persists, it may be that the SIM card is too old and does not work properly with modern security standards. 4G/5G and current encryption protocols in any salon.
⚠️ Note: If the phone is writing «SIM-Card is locked immediately after activation, do not try to enter PIN. The attempts are exhausted and it is necessary. PUK. Input incorrectly PUK will cause the card to be permanently damaged.
In rare cases, the problem may lie in the MIUI firmware itself. If the lock stops working after the system update, try resetting the network settings (Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth).
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The main problem of users is the loss of a plastic card from the PUK-Always take a picture of the card's circulation as soon as you buy a SIM card and save it in the cloud.