Why Xiaomi Mi4 see SIM-Map and how to fix it in 2026

Xiaomi Mi4, Launched in 2014, it still remains popular with users due to its robust "stuffing" and ability to upgrade to current firmware versions, but over time, owners face a typical problem: the smartphone ceases to recognize. SIM-Symptoms range from total network failure to periodic signal "disappearances", and 80 percent of the time, the fault is not due to hardware failures, but to software failures or mechanical damage to contacts.

In this article, we will discuss all possible reasons why Mi4 see SIM, — From the simple contamination of the slot to the damage to the communication module, you will receive step-by-step instructions with photos of key stages, a map compatibility table, and tips for diagnostics without going to the service center. Mi4: its two-sim slot is combined with a tray for microSD, which often leads to conflicts when installing cards incorrectly.

Primary diagnosis: Checkable SIM-slot

Before you sin on hardware malfunctions, rule out the simplest causes. Start with a visual inspection. SIM-card: its contacts must be free of scratches, oxidation (green or black) or mechanical damage. Mi4 “Does not see” it, the problem lies in the slot or smartphone software.

Make sure the SIM is properly installed in the tray. The Xiaomi Mi4 uses a hybrid slot (nanoSIM + microSD or second nanoSIM), and it is not uncommon for users to confuse the sides when installing. Notice the notch in the corner of the card - it must match the shape of the tray. If the card is inserted "upside down", the contacts will not come into contact with the connectors.

• 🔍 Examine the contacts of the slot: illuminate with a flashlight - there should be no dust, rust or bent "tissues" on the connectors».
• 📱 Check the card on another phone: if it doesn’t work there, the problem is SIM, not Mi4.
• 🔄 Reboot your smartphone: Sometimes the recognition failure is fixed by a simple reboot (clip the power) + Volume up for 10 seconds).
• 🛠️ Clean the slot: Use a dry brush or compressed air balloon (do not apply alcohol or wet wipes!).

⚠️ Warning: Do not use metal objects (needles, paper clips) to clean the slot contacts, this can damage fragile connectors. If you notice oxidation, gently wipe the contacts with a wipe (without pressing!).

2. Software failures: resetting settings and firmware update

If the mechanical part is fine, but the Mi4 still doesn't catch the network, the software is to blame.

• Missaddened MIUI update (especially when switching from Android 4.4 to 5.0+)
• Install custom firmware or root rights.
• The radio interface layer (RIL) is responsible for communication with the operator.

Start by resetting your network settings:

1. Go to Settings. → SIM-maps and mobile networks → Resetting network settings.
2. Confirm the action (password is not required).
3. Restart your phone and wait for automatic registration (it can take up to 5 minutes).

If this doesn’t help, do a full reset to factory settings (backup data is a must!):

1. Open Settings → Additional → Recovery and Reset → Resetting.
2. Choose Delete all data and confirm.
3. After the reboot, set the phone up as new and check the SIM.

If the reset doesn’t solve the problem, update the firmware via MIUI Recovery:

1. Download the latest stable version of MIUI for Mi4 from the official website (link).
2. Place the update.zip file in the root directory of internal memory.
3. Go to Settings → About Phone → System Update → Menu (three dots) → Select a firmware file.
4. Select the downloaded file and wait for the installation to be completed.

⚠️ Warning: Don't interrupt the upgrade process! If the battery is under 50%, plug in the charge. Mi4 It can turn into a brick (it won’t turn on).

3.IMEI problems: recovery and verification

One of the most insidious reasons for the lack of a network is loss or resetting. IMEI. This is a unique identifier of the phone, which "tethers" it to the network of the operator. IMEI It was destroyed (for example, after a failed firmware), Mi4 It will not be able to connect to the cellular network, even if SIM-card.

Check out the current IMEI:

1. In the phone app, type the combination *#06#.
2. If a 15-digit code is displayed instead of Null, Unknown or 000000000000000, the IMEI is lost.

To restore the IMEI on the Xiaomi Mi4, you will need:

• 📝 Original. IMEI (usually indicated on a sticker under the battery or on the box).
• 💻 Computer with ADB-Tools (Download Platform Tools).
• 🔧 Ruth-Right (if) IMEI dropped after firmware, they may not be - you will need to unlock the bootloader).

Instructions for recovery through ADB:

adb shell


su




echo 'AT +EGMR=1,7,"YE IMEI" > /dev/pttycmd1




echo 'AT +EGMR=1,10,"YE IMEI" > /dev/pttycmd1




reboot

Replace your IMEI with the original 15-digit code. After you reboot, check the network.

Hardware malfunctions: from slot to antenna

If the software methods didn't work, the problem lies in the hardware. Xiaomi Mi4 most often fails:

For self-diagnosis:

1. Check the slot with a multimeter: Put the device in resistance check mode (200 Ohms). Touch the contacts of the slot with probes (on the phone connector, not on the tray!). The resistance should be within 0.5-1.5 Ohms. If OL (cliff) or 0 (short circuit) - the slot is faulty.

Look at the antenna cable.

• Remove the back cover (need a mediator or plastic shoulder blade).
• Unplug the battery and find a thin black cable running from the motherboard to the top of the case.
• If the cable broke or broke, it was the reason for the bad network.

💡

Before disassembling the Mi4, warm up the back cover with a hairdryer (temperature 60-70 ° C) - this will soften the glue and reduce the risk of damage to the plumes.

5. conflict of two SIM-cards: features of the hybrid slot

Xiaomi Mi4 is equipped with a hybrid slot that supports either two nanoSIMs or one nanoSIM + microSD. Many users find that when you install a second SIM or memory card, the first one ceases to be recognized.

• 🔌 The wrong placement of cards: the second SIM It should be placed on the top slot (closer to the camera).
• 📶 The conflict between the operators: if both SIM From different providers, the phone can “hang” when switching between networks.
• 🛠️ Mechanical pressure: Too thick microSD (or adapter for it) can press the contacts first SIM.

Decisions:

1. Change the SIM places: install the main card in the upper slot, and the additional one in the lower one.
2. Turn off automatic network selection: Go to Settings → SIM-maps and mobile networks. SIM → Type of network → Only 3G (if the operator supports).

Use a microSD no thicker than 0.7 mm

💡

If the microSD system is gone, remove the memory card and see if it shows up, and if it does, it's a mechanical conflict problem, and you have to choose between a second SIM and a memory extension.

6. Alternative methods: debugging mode and engineering menu

If the standard methods didn’t help, try the hidden features of the Mi4:

Method 1: Engineering menu (to check the communication module)

1. Please dial the phone application ##4636##.
2. Select Phone Information.
3. Scroll down to the Set preferred network type block.
4. Try manually installing LTE/GSM auto (PRL) or WCDMA only.

Method 2: ADB Debugging Mode (for RIL reset)

1. Activate Developer Mode: Settings → About Phone → MIUI version (click 7 times).
2. Enable USB debugging in Settings → Additional → For developers.
3. Connect your phone to your PC and execute the commands: adb shell su setprop ril.radio.disabled false reboot

The cost of repairs in official Xiaomi services (for 2026):

Before the service visit:

1. Make a backup of your data (via Mi Cloud or TWRP).
2. Write down the IMEI (if it is displayed).
3. Check if the service has original parts for the Mi4 (many SCs work only with new models).

⚠️ Warning: Don't settle for "cheap" repairs using used parts or analogues. 90% of the time, this results in repeated breakdowns after 1-3 months. Xiaomi's official services give a 6-month warranty for replacement modules.

FAQ: Frequent questions on SIM-maps in Xiaomi Mi4