Owners of modern smartphones often face the need to improve the security level of their device, and the first step in this direction is to change the standard factory password on the device. SIM-By default, carriers set simple combinations like 0000 or 1234 that are easy for an attacker to pick up when physically accessing a gadget. MIUI, As used in Xiaomi, Redmi and Poco devices, the process of managing these settings is as simple as possible, but has its own hidden features that every user should know about.
Changing the security code is not just a formality, but an important procedure to prevent unauthorized use of your SIM card in someone else's phone. If the device is stolen or lost, an attacker will not be able to make calls or use the mobile Internet without entering the correct password, even if he extracts the chip from the smartphone. We will look at the detailed algorithm of actions for different versions of the shell, analyze typical errors and explain how to act in emergency lock situations.
It is worth noting that the menu interface may vary slightly depending on the version of Android and regional firmware, but the logic of the security system remains the same for all models of the brand. Below is an updated guide that will help you quickly set a strong password and protect your personal data from outside interference.
Set up a password request when turning on the phone
Before you change the digit combination itself, you need to make sure that the password request function is activated at all. Many new SIM cards have an automatic request by default, but after resetting the settings or rearranging the chip, this option can be deactivated. To turn on protection, go to the main settings of your Xiaomi and find the section responsible for network and connection settings.
In the menu you should select the item Protection SIM-cards, which are usually located in the "Security" subsection or directly in the settings list SIM-If you have a dual-sim machine, you'll see the "Request" switch here. PIN-The system will immediately ask you to enter the current standard password, which is most often indicated on the plastic basis of the SIM card or in the documents of the operator.
Once activated successfully, the smartphone will require you to enter numbers every time you turn the device on or remove the SIM card.This creates the first and most important barrier to unauthorized access. If you plan to change your SIM cards often, it makes sense to install complex code that is difficult to guess the first time.
Step-by-step change instructions PIN-Xiaomi code
The process of directly replacing the digital key takes no more than a minute, but requires care when entering data. A single-digit error can lead to a temporary locking of the input function, so follow the algorithm strictly by paragraphs. First, log in to the Settings menu → Passwords and Security → Privacy (the path can vary depending on the version of MIUI).
Find the System Security section and select the Settings option SIM-This menu will have the option to change the map. PIN-Click on it, and the system will ask for the current password, and once it is confirmed, you will need to enter the new combination twice from the 4-8 numerals.
☑️ Checklist before changing password
Use unique combinations that are easy to remember but hard to pick up by pumping, and once you change your password, your phone may suggest a reboot to apply the changes, although in most cases, it happens instantly.
Work with PUK-lock-in SIM-map
The situation where the user forgets the PIN and enters it incorrectly three times in a row is a classic one, at which point the SIM card is blocked and it is required to unlock it. PUK-Personal Unblocking Key: This is an eight-digit key that is issued by the carrier along with the SIM card and has nothing to do with the unlock codes of the phone screen.
Enter. PUK-The code can be directly in the input field, which will appear on the lock screen after the exhaustion of attempts to enter PIN. If you enter an infidel PUK-code 10 times, the SIM card will be permanently locked and can not be restored — you have to go to the communication salon for a replacement.
⚠️ Attention: Never enter PUK-It's more than three times in a row without any confidence that it's correct, and a mistake in entering that code causes the SIM chip to be permanently damaged.
Where do you find this code? It's printed on a plastic card that you used to squeeze your SIM card out of when you bought it. If the plastic is lost, you can find it in the subscriber's personal account on the operator's website or through support, after going through the identity process. Xiaomi devices sometimes display a hint that you need to enter a PUK, but the system does not know the code and cannot tell you.
What to do if PUK-code is lost too?
Managing Passwords for Two SIM-map
Xiaomi and Redmi are famous for their dual-SIM support, which creates some nuances in managing their security. Each SIM card has its own independent PIN, and you need to change them separately. In the settings menu, you will see a switch between SIM 1 and SIM 2, or separate items for each of them.
When you turn on a phone with two active SIM cards, the system can request passwords to be entered sequentially. To avoid confusion, it is recommended to use the same combinations for both cards, if your level of paranoia allows, or clearly differ to understand which card you are unlocking. The MIUI always clearly indicates which card you want to enter (for example, “SIM 1: Enter PIN”).
If you change the password on one card, the other one keeps running its old code, which is convenient if you only use one SIM card for the Internet and the other one for important calls, and you want to set different levels of protection, but for maximum convenience, it is better to synchronize the codes so that you don't have four different combinations in your head (two old and two new).
| Parameter | PIN-code | PUK-code | Where to find out. |
|---|---|---|---|
| Length | 4-8 digits | 8 digits | On-map. |
| Who's giving it away? | User (modified) | Operator (invariant) | Personal office |
| Attempts to enter | 3 attempts at | 10 attempts at trying | SIM lockdown |
| Appointment | Daily protection | Emergency unlocking | Documents of the operator |
Common mistakes and ways to solve them
One of the most common problems is entering a password on a locked screen when a user confuses the unlock code of the phone and the SIM card code. These are different things: the phone code removes the lock on the MIUI screen, and the SIM card code protects the operator's chip. If you entered the wrong SIM card code, the phone will prompt you to enter the PUK, rather than indefinitely requiring the same PIN.
Another common mistake is to use a keyboard with letters instead of numbers. The PIN field should only display a digital bar. If you have a keyboard with letters on, switch the layout, otherwise the system will not accept the input or give an error in the data format. On some global firmwares, the keyboard can adjust automatically, but in Chinese versions of MIUI this needs to be monitored.
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Tip: Take a photo of the PUK code and save it to the cloud or send it to your messenger, so you can always find it, even if the physical plastic card is lost.
If the phone writes “SIM Error” or “No Network” after entering the correct code, try restarting the device. Sometimes the modem drivers in Android may not properly process the change of SIM card protection status without rebooting. Also make sure that the SIM card is properly installed in the tray and the contacts are not contaminated.
Security features in different versions of MIUI
The security interface in Xiaomi is constantly changing. In older versions of MIUI (like 10 or 11), the SIM card settings often hid in the back of the “Advanced” menu. In newer versions (MIUI 12, 13, 14 and HyperOS), developers have brought these items closer to the surface, often combining them with the screen’s biometrics and password settings.
Owners of Chinese firmware versions should be more careful: menus may be called differently, and some security features can be integrated into Mi Security. PIN-Search the code, search by settings. Type the word in the search bar «SIM» or «PIN», The system will direct you to the right section.
It’s also worth mentioning the Device Security feature, which in new shells can require you to enter a SIM card password when you try to reset your settings to factory settings, an additional anti-theft measure that makes the phone useless for a thief even after a full reset if he doesn’t know the code from the SIM card and Mi Account.
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Main point: Regular shifts PIN-code and knowledge of PUK-Code is a minimal but critical safeguard to protect your mobile data and finances.