Why Xiaomi 9T Internet is bad and how to fix it yourself

Xiaomi 9T (He's a Redmi. K20 In the global version) – one of the most popular smartphones of the brand, but even it is not immune to problems with connection to the network. Poor mobile internet, Wi-Fi hangovers, or no signal can come on suddenly, after a firmware update, a device crash, or even for no apparent reason. 80 percent of the time, it's not hardware failures, but software failures or incorrect settings.

In this article, we will analyze all possible causes of weak Internet on Xiaomi. 9T — From the banal overheating to the hidden parameters of the modem, you will learn how to check the signal quality in the engineering menu, what settings are set up. APN It's relevant for Russian operators in 2026, and why a simple reboot in Fastboot sometimes helps. And if the problem is in hardware, we'll tell you how to distinguish a software failure from an antenna module failure.

Take your phone to the service, most malfunctions are solved in 10-15 minutes at home, and let's start with the simplest and gradually move on to advanced methods.

1. Diagnostics of the problem: how to understand what is the problem

Before you fix anything, you need to determine where exactly the "buried dog" is. 9T subdivided:

• 📶 Mobile network (4G/3G): weak signal, breaks in calls, inability to connect to the Internet through SIM-map.
• 📶 Wi-Fi: low speed, frequent connection breaks, phone 'can't see' some networks.
• 🔧 Hardware breakdown: physical damage to antennas, communication module or motherboard.

Start with a basic check:

1. Switch from mobile to Wi-Fi (or vice versa), and if the problem is only in one type of network, look for the cause there.
2. Check if the internet is working on other devices (such as a second phone or tablet) with the same device SIM-map or on the same Wi-Fi network.
3. Pay attention to the signal indicators: if a cross or exclamation point appears next to the antenna on the notification panel, this is a sure sign of hardware malfunction.

If the Internet is lost only on Xiaomi 9T, And other gadgets work fine -- the problem is your smartphone, and if the network is lying down on all devices, it's the operator (for mobile Internet) or the router (for Wi-Fi).

2. Software failures: reboot and reset settings

60% of cases are weak on Xiaomi 9T It's caused by temporary modem malfunctions or firmware conflicts:

Reboot to Safe Mode (Safe Mode):

• 🔄 Press the power button, then hold your finger on the option to Turn off – a prompt will appear to go to Safe Mode.
• 📱 This mode has disabled all third-party applications. If the Internet is working, it is the fault of one of the applications you installed (most often the one that is not installed). VPN, Antiviruses or “optimizers»).

Resetting network settings:

This option deletes all stored Wi-Fi networks, passwords and mobile Internet settings, but does not affect personal data.

1. Go to Settings. → SIM-maps and mobile networks → Resetting network settings.
2. Confirm action. Once you restart, the phone will create new configuration files for the modem.

Hard Reset is a last resort if nothing works. - Xiaomi 9T Resetting through the settings menu does not always clear the partition with the modem data, so it is better to use a button combination:

1. Turn off the phone.
2. Press Volume Up + Power before the Mi logo appears.
3. From the Recovery menu, select Wipe Data → Wipe All Data.

⚠️ Warning: If you have a problem after reset, don't rush to sew your phone. SIM-Card on another device: sometimes operators block cards for suspicious activity (for example, after frequent changes) IMEI).

3. Mobile Internet settings: APN, networking IMEI

Wrong parameters APN (hotspots are one of the most common reasons for the lack of mobile Internet, and even if the settings once worked, the operator could update them.

How to check and update your APN:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM] → Access points (APN).
2. Click on the three dots in the top right corner and select Reset to default values.
3. If it doesn’t help, add a new one. APN manually (see the table below for options for popular operators).

IMEI verification:

If after a firmware or reset, the mobile Internet disappeared, perhaps it flew off. IMEI (Unique device identifier, which can be verified by a team:

*#06#

If a 15-digit code is displayed as Null or Unknown — IMEI It can be restored through an engineering menu or special utilities (for example, Maui). META), But it requires root rights.

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If the firmware is gone after the change IMEI, Try to get the stock back. MIUI It's often a solution without manual repair.

Network mode:

In some regions, Xiaomi 9T catching 4G Because of the suboptimal settings on the modem, try manually setting the mode:

1. Go to Settings. → SIM-maps and mobile networks → [Yours. SIM] → Type of network.
2. Select Only. LTE (if 4G is not operating in a stable manner; or 3G (if 4G no catch).

4. Wi-Fi problems: channels, frequency and hidden settings

If Xiaomi 9T It's not good for Wi-Fi -- it can be the fault of both router settings and software bugs in smartphone drivers. Start by checking:

Optimal router settings for Xiaomi 9T:

• 📶 Channel: Use channels 1, 6 or 11 for 2.4 GHz (they are least congested). For 5 GHz, select a channel with minimal load (checked through applications like Wi-Fi Analyzer).
• 🔄 Mode of operation: Install 802.11n (for 2.4 GHz) or 802.11ac (for 5 GHz. Turn it off. 802.11b — He's slowing down the net.
• 🔒 Encryption: Only WPA2-AES or WPA3. TKIP And mixed regimes cause cliffs.

Hidden Wi-Fi settings on Xiaomi 9T:

V MIUI There are undocumented parameters that affect the stability of Wi-Fi:

1. Turn on Developer Mode: Go to Settings → About Phone and click on MIUI Version 7 times.
2. Go back to Settings → More → For developers and find:
3. Aggressive Wi-Fi switching – turn off (this will reduce the number of automatic connections to weak networks).
4. Wi-Fi mode – Always select (so that the phone does not disconnect from the network in sleep mode).

The problem with 5 GHz:

Xiaomi 9T supports 5GHz band, but sometimes "doesn't see" the network in this mode:

• 🔌 Router uses channels above 149 (not supported in Russia).
• 📡 5 GHz module is disabled in the firmware (solved by flashing or changing the region to India in the engineering menu).

Hardware malfunctions: antennas, plumes and overheating

If the software methods didn't help, the problem could lie in the "hardware" Xiaomi has. 9T It has three antennas: the main one (for mobile network), Wi-Fi/Bluetooth and GPS. Any damage to any of them affects the quality of communication.

Signs of hardware breakdown:

• 📵 The Internet disappears when the phone is tilted or pressed on the case (damaged antenna plume).
• 🔥 The phone is strongly warmed in the upper part (modem overheating).
• 🛠️ After falling or getting moisture, the signal became worse (the contacts were detached).

How to check:

1. Antenna Test: Dial ##4636##, Go to Phone Information and look at Signal Strength metrics. -100 dBm - signal is very weak.
2. Train check: Carefully tap the top of the phone (where the antennas are located). If the signal changes, the plume or contact is to blame.
3. Diagnostics of overheating: Install the app AIDA64 Check the temperature of the processor if it's above 60.°C to simple - the modem overheats.

What to do:

• 🛠️ If the plume is to blame - it can be replaced yourself (the cost of the part) ~500-800 rubles).
• 🔥 If overheating, try changing the thermopast on the processor (disassembly is required).
• 📡 If the antenna is damaged, only a replacement in the service (price) ~1500–2500 rubles).

⚠️ Warning: If the phone falls or gets wet, do not try to disassemble it yourself - corrosion on the board can lead to short circuit.

6.Firmware and modem: Update, Downgrade and patches

Xiaomi. 9T The quality of the connection depends on the firmware version. MIUI (especially custom) there are bugs in the modem drivers, because of which the phone "does not see" part of the frequencies 4G or does not work well with 5 GHz Wi-Fi.

How to update the firmware correctly:

1. Check the current version in Settings → About Phone → MIUI version.
2. Download the latest stable firmware for your model from the official Xiaomi website (not beta!).
3. Install through Settings → Update the system (if available) or manually via Recovery.

Downgraid firmware:

If the problem started after the update, you can roll back to the previous version.

1. Download the necessary firmware (for example, with Xiaomi Firmware Updater).
2. Unpack the archive and place the.zip file in the root of the phone’s memory.
3. Go to Settings → About Phone → System Update → Three Dots → Select a firmware file.

Patches for modem:

In some cases, the firmware of the modem separately helps (without a complete flashing of the phone).

1. Download the modem file for your version MIUI (Look for forums like this. 4PDA or XDA Developers).
2. Fastboot command: fastboot flash modem [name file].img

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If it's gone after the firmware. IMEI Or the signal deteriorates, return to the stock. MIUI via Mi Flash Tool with Clean All option. Custom firmware often breaks the modem.

Alternative solutions: from VPN replace SIM-map

If the standard methods don’t work, try the non-obvious methods:

1. Shift SIM-map:

• 📱 Old ones. SIM-cards (especially Mini-SIM) may not come into contact with the slot, try trimming it to Nano-SIM or replacing it with a new one in the operator’s cabin.
• 🔄 If you use eSIM, check its profile in operator settings – sometimes you need to reactivate it.

2. VPN proxy:

Some operators limit speed for certain types of traffic. VPN This helps to circumvent these limitations:

• Install Cloudflare WARP or ProtonVPN.
• Turn it on. VPN Check the speed of the internet (for example, through Speedtest).

Alternative launchers:

In rare cases, network problems are caused by shells like Nova Launcher or POCO Launcher.Go back to the standard launcher. MIUI and check the link.

Region of telephone:

Xiaomi 9T may limit the frequency 4G depending on the region you choose, to change it:

1. Install the Activity Launcher app.
2. Find activity Country/Region Selector and run it.
3. Select India (this region supports maximum frequency). 4G).

8 When there is only a service center left

If you have tried everything on this list, the Internet is on Xiaomi. 9T It's still not working well -- it's probably hardware. Here are the signs you should go to the service:

• 📵 The phone does not catch the network at all (even after resetting and firmware).
• 🔌 The signal disappears at the slightest movement (damaged antenna plume).
• 🔥 Modem overheats to 70°C+ and shuts down (chip malfunction).
• 💧 The phone fell into the water or was hit hard.

How much will the repair cost:

How to choose a service:

• 🔧 Preference is given to official partners of Xiaomi (list on the website mi.com).
• 📋 Check if you have a warranty for repairs (at least 3 months).
• 💬 Read reviews about the workshop on Yandex.Maps or 2GIS.

⚠️ Warning: If the phone is warranty, do not open it yourself - this will void warranty obligations.

FAQ: Frequent questions about the Internet problems on Xiaomi 9T