How to open the port for SIM-Maps on Xiaomi smartphones: 5 working ways

Mobile phone problems on Xiaomi smartphones are one of the most common user complaints, ranging from a total lack of network to periodic call interruptions or slow Internet. SIM-Maps are software limitations that can occur after a firmware update, operator change, or incorrect settings. SIM-Why it can be closed and how to open it without risking damage to the device.

Many people mistakenly believe that the "opening of the port" is associated with a physical connector under the sea. SIM-It's actually about software unlocking access to network frequencies and protocols that your carrier uses, for example, if the Redmi Note 12 doesn't catch the MTS network, but it works with Tele2, the problem is probably the port settings. The procedure does not require soldering or disassembling the device - everything is solved through menus or engineering commands.

What is a port? SIM-The maps and why they are blocked

Term "port" SIM-"cards" in the context of Xiaomi means a virtual communication channel through which the smartphone communicates with the operator's network. It is not a physical connector, but a set of settings that includes a set of settings:

• 📡 APN-Profiles – Internet connection parameters and MMS;
• 🔄 Network modes - support 2G/3G/4G/5G and their priorities;
• 🔒 IMEI-binding – the device identifier that the operator checks when registering in the network;
• 📶 Frequency bands – a list of supported radio channels (e.g. Band 3, Band 7).

A port lock can occur for several reasons:

1. Update to firmware: Newer versions of MIUI sometimes reset network settings or make changes to frequency access policies. For example, after upgrading to MIUI 14, many Poco X5 Pro users experienced the loss of the MegaFon network.
2. Change of operator, if you've moved SIM-The card from one phone to another, old APN-settings may conflict with new network parameters.
3. Hardware reset. After Hard Reset, the smartphone returns to factory settings, where the port SIM-Default cards may be limited.
4. Software bugs: Modem bugs or conflicts with applications (such as Dual Apps) also lead to blocking.

⚠️ Note: If the smartphone has stopped seeing SIM-If you're in a map after a drop or a moisture hit, it's probably a hardware problem, and if you're in a port opening, software won't help, you need to diagnose the connector or the antenna module.

Method 1: Verification and discharge APN-settings

In 60 percent of cases, the problem is solved by adjusting the APN hotspot, which is especially relevant if the smartphone sees the network but does not connect to the mobile Internet.

1. Open the Settings. → SIM-maps and mobile networks.
2. Choose a problem SIM-card (if two of them).
3. Go to Access Points (APN).
4. Click on the three dots in the top right corner and select Reset to default values.
5. If the reset didn’t help, add the APN manually (options can be requested from the operator or found on its website).

Example of correct APN-MTS settings:

After saving the settings, restart your smartphone. If the network indicator appears, but the Internet still does not work, check the balance and activity of the tariff plan with the operator.

💡

If there are multiple profiles with the same name on the APN list, delete everything and add one new Duplicates often cause conflicts.

Method 2: Engineering menu (codes for unlocking the port)

For advanced users, there is a method of unlocking through the engineering menu, which is suitable if the APN reset did not help, and the smartphone does not see the network at all. Attention: improper actions in the engineering menu can lead to the loss of IMEI or modem breakdown.

Instructions for models on Qualcomm processors (for example, Redmi Note 11 Pro+, Poco F4):

1. Open the phone app and enter the code: ##4636##
2. In the menu that opens, select Phone Information.
3. Scroll down to the Network Installation block.
4. In the Set preferred network type field, select LTE only (or) NR/LTE/TD-SCDMA/GSM for 5G-model).
5. Click Update and restart the device.

For smartphones on MediaTek (e.g. Redmi 10C, Poco M5), use the code:

##36446337##

From the Engineer Mode menu, go to Connectivity → BandMode and enable all supported bands (e.g. LTE Band 1/3/7/20 for Russia).

⚠️ Note: If after changes in the engineering menu, the smartphone stopped seeing any networks, reset the network (Settings) → System system → Network reset. That'll bring the modem back to the factory.

Make a backup of IMEI (IMEI Backup app)

Write down the current APN settings

Battery charge of at least 50%

Do not interrupt the process of changing parameters.-->

Method 3: Resetting network settings

If previous methods didn't work, do a full reset of network settings, which will delete all stored Wi-Fi networks, passwords, APN Bluetooth settings, but often solves port problems SIM-map.

Instructions:

1. Go to Settings. → The phone.
2. Click on Resetting (or Backup and Reset in older versions of MIUI).
3. Select Network Resetting.
4. Confirm the action and wait for the reboot.

After resetting, the smartphone will automatically select the APN settings for your carrier. If this does not happen, add them manually (see Method 1).

Method 4: Update the modem firmware

In rare cases, the port SIM-The card is blocked because of an outdated version of the modem firmware, the firmware that runs the network modules:

• 📱 Smartphone does not see the network after the update MIUI;
• 🔄 Often the signal is lost or calls are interrupted;
• 📶 The engineering menu displays the Modem crash error.

To update the modem firmware:

1. Find out the exact model of your smartphone (for example, Redmi Note 10 Pro – sweet, Poco X3 Pro – vayu).
2. Download the current modem firmware from the Xiaomi Firmware Updater site (Modem section).
3. Install it via Fastboot or TWRP (unlocked bootloader required).

Example of commands to install via Fastboot:

fastboot flash modem NON-HLOS.bin


fastboot reboot

⚠️ Attention: Inconsistency of the modem firmware version and the main firmware MIUI This may cause total network loss. Check file compatibility before upgrading!

Method 5: IMEI verification and network binding

If the smartphone does not see SIM-The card does not even define the operator, the problem can be hidden in the IMEI — A unique device identifier, lost or blocked by the operator, makes it impossible to log in to the network.

To check the IMEI:

1. Enter the phone app: *#06#
2. Compare the number displayed with what is indicated on the box or under the battery (for models with a removable battery).
3. If IMEI is missing (null), restore it through an engineering menu or specialized utilities (for example, Maui META for MediaTek).

To link the IMEI to the operator’s network:

• 📋 Contact the communication salon with a passport and a contract for services;
• 🔄 Ask for a re-registration IMEI operator-base;
• 📱 If the smartphone is purchased abroad, it may be necessary to officially break it (for example, for Xiaomi sold in China).

💡

Loss of IMEI is a critical problem that cannot be solved by software without specialized hardware. If the IMEI is reset after firmware, contact the service center.

Frequent Mistakes and How to Avoid Them

When you try to open the port SIM-And so, you can see that users often make mistakes that make the problem worse:

Another common mistake is ignoring regional firmware: Xiaomi smartphones purchased in China (ROM) often have restrictions on working with Russian carriers, in which case you need to use Global or EEA versions of MIUI.

If you're not sure what you're doing, you should go to the service center. SIM-maps in official centers Xiaomi starts from 500 rubles.

FAQ: Answers to popular questions