How to turn on the second SIM-Map Xiaomi Redmi Note 9: all ways

Xiaomi Redmi Note 9 remains one of the most popular smartphones in the budget segment even years after its release. SIM-However, many users face the problem: the second line is not defined, does not catch the network or simply is inactive in the menu. SIM, including hidden settings MIUI and solving typical errors.

It is important to understand that the setup process depends on the firmware version (MIUI 12/13/14), the carrier and even the region of purchase of the device. For example, in the European versions of the Redmi Note 9 (model M2003J15SG) there may be no support for VoLTE on the second SIM, which requires additional manipulation. We tested all methods on current firmware in 2026 - below only proven solutions.

Verification of two support SIM-maps in your model

Before you try to activate the second line, make sure that your Redmi Note 9 supports dual-sim mode at all. There are 3 modifications to the Redmi Note 9 line:

📱 Redmi Note 9 (Global) — 2 nano-SIM + MicroSD (hybrid slot) Model number: M2003J15SG.
📱 Redmi Note 9 Pro — 2 nano-SIM + microSD. Model number: M2003J6A1G or M2003J6B1G.
📱 Redmi Note 9S/Pro Max — 2 nano-SIM + microSD. Model number: M2003J15SC.

To find out the exact model:

Open the settings → About the phone → Model.
Or enter the combination in the dialer: ##4636## → Go to the Device Information tab.

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If the specifications indicate "Dual SIM", but the slot one is a hybrid option, priority is given to either the second SIM or the memory card (it will not work simultaneously).

Also check the regional firmware:

🌍 Global (EEA) — The official firmware for Europe supports both SIM.
🇨🇳 China may block the second SIM mapless.
🇷🇺 Russia – adapted for local operators (MTS, Beeline, Tele2).

📊 What version? MIUI use?

MIUI 12

MIUI 13

MIUI 14

I don't know.

other

If your smartphone supports two cards but the other card is inactive, start with the standard procedure:

Put both in. SIM-cards in the respective slots (usually) SIM 1 - top slot, SIM 2 - lower). For the hybrid slot, select priority: either the second SIM, microSD.
Reset the device (required!).
Open the Settings. → SIM-maps and mobile networks.
Slip on the inactive SIM (it will be marked as "Disabled").
Activate the switch Turn on SIM-map.
Choose the type of network (recommended 4G for voice and data).

If the paragraphs are inserted SIM-No card, there's a problem with the hardware or firmware.

Insert both SIMs in the correct slots |

Reboot the phone |

Update MIUI to the latest version|

Check the compatibility of operators (not all support) 4G second SIM)-->

SIM Priority Setting for Calls and the Internet

Once the second line is activated, you need to adjust its behavior. MIUI This is done through the Settings menu. → SIM-maps and mobile networks → Double settings SIM. Options are available here:

Parameter	Description	Recommendation
SIM for calls	Selecting a card for outgoing calls by default	Always ask to choose before calling.
SIM for SMS	Default Messages Card	Choose the main operator SIM with the best coverage
Mobile data	SIM for transferring Internet traffic	Choose a card with unlimited tariff or the best 4G
VoLTE	Voice over LTE (allows you to call while using the mobile Internet)	Enable both SIMs if supported by the operator

If you have chosen SIM 2 for mobile data and it does not catch 4G, check:

📶 Does the operator support the 4G second SIM (Tele2 may limit the number of).
🔄 Is the regime on? 4G/3G/2G (auto) in the network settings.
🔧 Is the firmware updated to the latest version (in older versions) MIUI 12 were bugs with the second SIM).

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If the second SIM does not catch the network, first check it in the first slot - this will help determine whether the problem is in the card or in the slot.

Solving problems with a broken second SIM

If the second line is still inactive after the basic setup, the reasons may be as follows:

1. Hardware problems

Check it out.

🔌 Slot contacts - gently wipe with alcohol if oxidized.
📏 Correct installation — SIM It should be entered before clicking (on the Redmi Note 9 slot is located on the left).
🔧 Tray damage – if the slot is bent, the card will not contact.

2. Programmatic failures

Try it:

🔄 Restart in Safe Mode (click the power button) → Restart in safe mode if the second SIM It is the fault of the third-party application.
📲 Resetting network settings: Settings → SIM-maps and mobile networks → Resetting mobile network settings.
🔧 Update the firmware through Settings → The phone. → Updating the system.

Problems with the operator

In 2026, some Russian operators (e.g. Yota) block the second SIM on Xiaomi due to the limitations of Roaming protocols.

📞 Call the operator and request the activation of Dual service SIM Support (sometimes paid).
🔄 Manually add it. APN: Settings → SIM-maps and mobile networks → [Choose. SIM] → Access points (APN) → Add.

How to Manually Add APN to a Second SIM

1. Name: Internet (or as the operator). 2. APN: Internet.mts.ru (for MTS), Internet.beeline.ru (for Beeline), etc. 3. Authentication type: PAP or CHAP. 4. Save and restart the phone.

Hidden MIUI settings for the second SIM

If standard methods don't work, use the engineering menu or hidden codes, which work on MIUI 12-14, but you need to be careful.

For MediaTek-based devices (e.g., Redmi Note 9 with Helio G85 chipset):

Enter the dialer: ##4636###
Go to the Device Information tab.
Scroll down to the Set preferred network type block.
Select LTE/WCDMA/GSM auto for the second SIM.

Method 2: Activation code for the second SIM

Enter sequentially (after each code, click "Call"):

##4636## → Verification of SIM
##2263## → Frequency band check
##0011## → Test of the communication module

If the second SIM appears as OFF after entering ##0011##, the problem is in the hardware.

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After using the engineering menu, restart the phone - changes apply only after the reboot.

Features of the two SIM on the Redmi Note 9

Even after successful activation of the second line, nuances may occur:

📶 Limitation 4G: on some firmware SIM only works 3G, Even if the operator supports 4G. The solution is to update MIUI or use the Magisk patch (requires root).
🔋 Increased battery consumption: two active SIM increase energy consumption by 10-15%. Disable Network Search for Unused Card in Roaming.
📞 Conflicts of the Call: If both SIM It's going in at the same time, and it's only going to work the first one.

Also consider:

🌐 Roaming: when traveling abroad, the second SIM It can be automatically shut down due to operator restrictions.
📱 Updates: After major updates MIUI second-tune SIM may be dropped.

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On the Redmi Note 9 with MIUI 14 firmware, the second SIM can lose network after rebooting. The solution is to disable the "Auto-Network Selection" option in the SIM settings.

Frequent Mistakes and How to Avoid Them

User experience shows that most of the problems with the second SIM on the Redmi Note 9 are due to incorrect configuration actions.

⚠️ Attention: Never take out SIM-If you have a card on, it can damage the slot contacts. Always turn off the device before changing the cards.

❌ Using a microSD instead of a second SIM: In a hybrid slot, you can not use a memory card and a second one at the same time. SIM. Priority is given to what is inserted last.
❌ Incompatible operators: some virtual operators (e.g. Tinkoff Mobile) do not support the second operator. SIM.
❌ Resetting settings without backup: when resetting to factory settings, the second parameters SIM They will reset and have to reset it.

Another common problem is that the second SIM is not in the status bar, which doesn't always mean that the card isn't working.

Open Settings → Notifications and Status bar → Status signs.
Make sure the SIM card display is enabled.

How to check if the second SIM works without an icon

1. Try calling the number two. SIM from another phone. 2. Send. SMS second SIM (Even if the icon is not, the function can be active. 3. Check the balance through USSD-request (e.g. *100#).

FAQ: Answers to popular questions

Can I use two SIMs and a memory card at the same time on the Redmi Note 9?

No. In a hybrid slot, you can either choose a second SIM or a microSD, and you can't have all three of them running at the same time.

Why does the second SIM only work in 2G, even though the carrier supports 4G?

This is a firmware limitation. Solutions: Update MIUI to the latest version. In the engineering menu (#4636##) manually select LTE only mode for the second SIM. Install custom firmware (e.g. Pixel Experience) if official methods don't work.

How to transfer contacts to the second SIM?

MIUI does not have a built-in SIM export function. Use the workaround: Export contacts to.vcf via Contacts → Settings → Import/Export. Send the file to the mail or messenger. Open the file on another phone and save contacts to SIM. Return SIM to Redmi Note 9.

The second SIM is detected, but it doesn't catch the network. What do we do?

Try: Reinstall SIM to another slot (if the first one is working, the problem is in the slot). Reset the network settings (Settings) → SIM-map → Reset mobile network settings to check if blocked SIM The operator (sometimes the unblocking is required) IMEI).

Can you make the second SIM the main one for the Internet and the first one for calls?

For this: In Settings → SIM-maps and mobile networks → Mobile data select the second SIM. B Settings → SIM-maps and mobile networks → SIM For calls, select the first one. SIM. Activate VoLTE for both cards if the operator supports. SIM, A calls through the first.