Xiaomi Redmi doesn't see SIM-Map: Complete guide to elimination

When your Xiaomi Redmi suddenly stops seeing a SIM card, it can be taken by surprise at the most inopportune moment: the screen remains empty, the status bar appears crossed out icon or the words “No SIM”, and calls and mobile Internet are unavailable. This is a common problem faced by owners of both budget models and flagship devices of the Mi and Redmi Note series.

The reasons for this behavior of the smartphone can range from the banal physical contamination of contacts to software failures in the modem or damage to system files. Often users begin to panic, suggesting that the device itself is broken, but in most cases, the problem can be solved independently without contacting the service center.

In this detailed guide, we'll look at all the steps of diagnostics, from simple cleaning of the tray to complex manipulation of the engineering menu and flashing. It's important to keep the steps in mind, because sometimes the solution lies in little things that are easy to overlook on a superficial inspection. Let's look at why Android on your device stopped identifying the carrier.

Primary diagnosis and physical examination of the tray

The first thing to do if a Xiaomi phone doesn't see the SIM is to eliminate mechanical damage and contamination. The SIM card tray is a movable element that is constantly exposed to dust, pile and oxidation. Even a microscopic speck of dust on the gold contacts can disrupt the electrical contact between the card chip and the motherboard.

Remove the tray with a paper clip and carefully examine it under bright light. Pay attention to the position of the contacts: they should be smooth and clean. If you notice oxidation or dirt, gently wipe the contacts with a soft rod or cotton swab slightly soaked in alcohol. It is important not to use aggressive chemicals that can damage the plastic base of the card.

Also check the SIM card itself for chips and scratches. If the card has been in use for several years, its contacts could just wear out, in which case the solution would be to replace the SIM card with your carrier, since modern communication standards require the perfect state of the chip.

• 🧹 Carefully wipe the SIM card contacts with a dry soft cloth.
• 🔍 Inspect the tray for warping or stuck dust.
• 🔄 Try inserting the SIM card into another slot if you have two.
• 📱 Check if the card sits tightly in the tray and if it is not hanging.

⚠️ Warning: Never try to insert the tray back if the SIM card is installed incorrectly or protrudes beyond the edges of the tray.This can cause the reader mechanism inside the housing to break.

Sometimes the problem is not the map, but the tray itself, which may have deformed after falling, and if the tray enters the device with difficulty or, conversely, falls out, the geometry of the body may be disturbed, which affects the pressing of the contacts.

Network settings and modem operation

If the physical examination does not reveal any problems, then you should go to the software part. Often, the settings of the mobile network are knocked down the parameters necessary to identify the operator. MIUI or HyperOS is responsible for this section «SIM-maps and mobile networks».

Go to the settings and make sure that the desired slot is activated. Sometimes after a system update or accidental failure, the SIM card slider may switch to the off position. It is also worth checking the settings of the preferred network type. If you select 5G only or 2G only mode, and in your area such networks are not caught or the SIM card does not support them, the phone may show no connection.

Try manually selecting a carrier, go to the operator selection menu, turn off the automatic search, and wait for the list of available networks to appear, if your carrier appears on the list, force it, which will help you understand whether the modem sees the network at all.

• 📶 Switch the network mode to “Preferred” LTE» or «3G/2G» check out.
• 🔌 Activate and deactivate flight mode on 10-15 seconds.
• 📲 Make sure the settings do not include Do Not Disturb mode for calls.
• 🌐 Reset the access point settings APN factory-level.

On some older SIM cards or certain carriers, switching to IPv6 may cause conflicts. Try changing the APN type to IPv4/IPv6 or IPv4 only.

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Try temporarily disabling the second SIM card in your settings. Sometimes a priority conflict between two active slots causes the phone to stop seeing one of them.

Network reset and software errors

Accumulated errors in the system files responsible for communication can block the modem, which often happens after a failed firmware update or installation of applications requiring deep access to the system, the most effective way to fix such failures is to reset the network settings.

This procedure won't delete your personal data, photos or contacts, but will return all network settings to factory values.You'll have to re-enter passwords from Wi-Fi networks and configure Bluetooth pairings, but this often brings the SIM card to life.The path to the feature is usually at: Settings → Connection and Sharing → Reset Wi-Fi, mobile networks and Bluetooth.

If a simple reset didn't work, you can try a more radical method, which is cleaning the system's application cache. Go to the application menu, find the phone or settings system app, and select cache cleanup (not data if you're afraid of losing settings, although you can try the data for diagnostics).

In rare cases, the problem may be related to a specific MIUI update. If the problem appeared immediately after the update, it makes sense to search the forums about bugs of this version of the firmware.

IMEI check and work with the engineering menu

One of the most important reasons why Xiaomi does not see the SIM is the SIM. IMEI-code. IMEI — This is a unique identifier for your device on the network, and if the modem's database loses or is corrupted, the phone will not be able to physically log in to the operator's network, even if the SIM card is in good working order.

You can check the IMEI status by typing *#06# in the dialer code. If you don't see anything on the screen or you see zeros instead of numbers, that's the problem, and the indicator can also be the absence of signal level icons even when you insert the card.

For a deeper diagnosis, you can use the engineering menu. Type ##4636## in the dialer. The hidden test menu will open. Select Phone Information. Here you can see the connection status and try to run the SIM Toolkit test. If the IMEI fields are empty, you will need to restore through special utilities (for example, Maui Meta or SN Writer), which requires the presence of a PC and drivers.

• 🔢 Enter *#06# to quickly check for availability IMEI.
• ⚙️ Use the code ##4636## to access the modem tests.
• 📉 Follow the “Connection Status” option in the Engineering Menu.
• 🛠 Not in the absence IMEI You may need to reflash (partitions) of the modem.

⚠️ Warning: Changing the settings in the engineering menu without understanding their purpose can lead to complete loss of communication!

IMEI recovery is a complex procedure and on some models (especially with Snapdragon processors) requires an unlocked bootloader and Root rights. If you are not confident in your abilities, you should consult a specialist.

Hardware malfunctions and soldering of contacts

When software is exhausted, we have to talk about hardware. In Redmi and Xiaomi smartphones, a common problem is the flow of the antenna plume or the oxidation of the contact pad on the motherboard itself, which often happens after falls or moisture.

If the phone fell, the connector connecting the board to the antenna module could move away. Visually, this is not always noticeable, but the signal will be extremely weak or absent at all, and the SIM card reader itself (the contact group inside the phone) could be damaged. Over time, the spring contacts inside the connector will fall and stop touching the chip.

Diagnosing these malfunctions requires disassembling the device, removing the back cover (or opening the screen if the unibody design) and inspecting the internal components, looking for signs of corrosion, battery bloating (which can put pressure on the board), or severed plumes. Replacing the SIM reader is a common service in service centers that is usually inexpensive.

• 💧 Check the fee for traces of oxidation or moisture.
• 🔌 Check the density of all plumes, especially the antenna.
• 🔋 Remove the battery (if possible) and check the contacts below it.
• 🔨 Carefully bend contacts in the SIM card slot if they slipped.

And there's a rare but possible problem, which is that the radio itself is going to fail, and it's the circuitry on the board that's responsible for communication, and it requires professional equipment and soldering skills to replace it.

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If after replacing the SIM card and resetting the phone still does not see the network, the probability of hardware failure is more than 80%.

The card is not determined after firmware or reset

A separate layer of problems arises after installing custom firmware or global versions of software on Chinese versions of smartphones, when flashing it, the EFS or Persist section, which stores calibration data for the radio module, could be damaged.

If you've been flashing your phone yourself, remember if you've backed up those partitions. Without them, the phone becomes a "brick" in terms of communication. The problem may be frequency incompatibility. The Chinese versions of Xiaomi may not support some LTE frequencies (Band 7, Band 20), which are widely used by European carriers, in which case the phone will see the SIM card, but the network will not catch or will constantly switch to 2G/3G.

The solution is to return to stock firmware through the Clear All Mi Flash Tool, which is guaranteed to restore the original partition structure, and if the problem is lack of frequencies (hardware feature), only replacement (motherboard) or external signal amplifiers will help, which is rarely advisable.

Sometimes it helps to manually select the frequency range through the engineering menu (code ##4636## -> Phone Information -> Set Preferred Network Type). Try selecting LTE Only or WCDMA Preferred mode and see if the signal appears.