Xiaomi Redmi 9 reboots on its own: reasons and what to do

Owners of Xiaomi Redmi 9 often face a nasty problem: the phone suddenly turns off and turns on for no apparent reason. This can happen just 5 minutes during the game, and in the middle of the night when the device lies idle. spontaneous reboots are not only annoying, but also signal possible malfunctions - from software failures to hardware breakdowns.

In this article, we’ll look at all the possible reasons why the Redmi 9 reboots itself, from overheating to motherboard damage, how to diagnose the problem yourself, which settings to check first, and when to contact the service center. And also – step-by-step instructions for eliminating each of the causes, including hidden chips MIUI, Even the official manuals are silent about.

If your phone reboots regularly (e.g. every 10 to 30 minutes) or only in certain situations (when charging, playing, in the cold), this will help narrow down the possible culprits. Don't rush to carry the device for repair - in 70% of cases, the problem can be solved with your own hands in 10 to 20 minutes.

1. Processor overheating: the most common cause

Redmi 9 is powered by MediaTek Helio processor G80, It's prone to overheating when you're under high stress, if the phone spontaneously reboots during games (PUBG Mobile, Genshin Impact, video shooting in 4K or with prolonged use of the navigator - it is the thermal throttling that is to blame (emergency shutdown due to critical temperature).

Normal operating temperature for Redmi 9 - up to 45-50°C. At 60°C+ It forcibly restarts the device to prevent damage to the chipset, and you can check the temperature through applications like this. AIDA64 or CPU Monitor.

• 🔥 Games and heavy apps: Even 15 minutes of Call of Duty Mobile can heat up the processor to critical values.
• ☀️ Direct sunlight: left on the windowsill phone heats up to 50°C+ few minutes.
• 🔌 Charging. + load: Simultaneous play and connection to the charger doubles heat release.

⚠️ Warning: If the phone refuses to turn on for 5-10 minutes after rebooting, this is a sign of critical overheating of the battery. Do not try to start it again immediately: wait for the battery to cool down completely (the body should be barely warm).

How to reduce heat:

1. Remove the cover during games or charging.
2. Turn off background processes in Settings → Annexes → Auto-start.
3. Lower your game schedule to Medium or Low.
4. Use a cooling stand (for example, with a fan).

2. Firmware failures MIUI: bugs and conflicts

Operating system MIUI (Especially versions 12.0-12.5) are famous for its "surprises." If the phone started to reboot after the update, it is the fault of a software conflict or incorrect firmware:

• 📱 Reboot when unlocking the screen.
• 🔄 Cyclical reboot (phone turns on, shows Redmi logo, turns off again).
• 🛑 Hanging on the logo MI afterswitching off.

How to check the MIUI version:

1. Go to Settings → About Phone → MIUI version.
2. Compare this to the latest stable builds on the official website miui.com.

If the version is outdated or is a beta firmware (designated as Developer), it needs to be updated urgently, but there is a caveat: sometimes an update is made over the air" (OTA) It doesn't solve the problem, it makes it worse. In such cases, only a clean installation via Fastboot will help.

Download the official firmware with [miui.com](https://miui.com/)|Check the battery charge (minimum) 50%)|Make a backup copy of the data|Disable antivirus on PC|Prepare. USB-cable (original)-->

Instructions for resetting to factory settings (if flashing did not help):

1. Turn off the phone.
2. Press the Power button + Volume up for 10 seconds.
3. From the Recovery menu, select Wipe Data → Wipe All Data.
4. Confirm the action and wait for the completion.

⚠️ Warning: Reset will delete all data, including photos and messages. If the phone doesn't even turn on in Recovery, you'll need firmware via Fastboot from your PC.

3. Battery problems: wear and bloating

Redmi 9 comes with a 5020 mAh battery, but its performance deteriorates over time.

• 🔋 Reboots at a charge level of 20-30% (suddenly switches off, as if the battery has died).
• 🌡️ Heated in the battery area even without load.
• 📉 Fast discharge (from 100% to 0% in 3-4 hours).

These are signs of wear and tear or bloating, and you can check the status of the battery through the AccuBattery app. If the storage capacity is below 80%, it's time to change the battery.

A bloated battery is a time bomb. If you notice that the back of the phone has become convex or the screen is moving away from the case, immediately disconnect the device and do not use it until the battery is replaced. The risk of fire or explosion during further use is extremely high!

4. Application conflicts and viruses

Sometimes the culprit for spontaneous reboots is one "curved" application that conflicts with the system.

• 🎮 Pirate Games or Modified Games APK.
• 🔍 Acceleration/cleanup applications (e.g. Clean Master, DU Speed Booster).
• 📊 Unofficial launchers or topics for MIUI.
• 🦠 Viruses and Mining Bots (CPUs are secretly used).

How to find a problem application:

1. Launch your phone in Safe Mode (click the Power button) → Hold it down. → Choose Safe Mode).
2. If the reboots have stopped, one of the installed applications is to blame.
3. Remove suspicious programs, starting with the last ones installed.

To check for viruses, use Malwarebytes or Dr.Web Light. Pay attention to applications with device administrator rights (settings). → Security → Device administrators – they are often used by mining bots.

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If the phone reboots when you open a particular app (like Tinkoff Bank or VKontakte), try clearing its cache: → Annexes → [Name of name] → Clear the cache. If it doesn't work, re-install it.

5. Malfunctions of the motherboard and contacts

If all software methods have been tried and Redmi 9 is still restarting, the problem may be in the hardware:

• 🔌 Oxidation of battery contacts or charging port.
• 🔧 Chip dump (especially after falls or bumps).
• 📡 Failure of the power module (often manifested when charging).
• 🔋 Short circuit on the board (the phone may even smoke).

It is difficult to diagnose hardware faults on your own, but there are indirect signs:

• The phone reboots whenever you touch the body (bad battery contact).
• Artifacts (strips, flickering) appear on the screen before turning off.
• Charging is jerking or the phone does not recognize the cable.

If you are versed in electronics, you can check the board with a multimeter:

1. Remove the back cover (need a mediator and a hair dryer to soften the glue).
2. Disconnect the battery and check the voltage on the contacts (3.7–4.2V — norm).
3. Check the board for darkening, swollen capacitors or chipped elements.

⚠️ Note: If you have no experience in the squashing BGA-Don't try to repair the board yourself, improper heating can permanently disable it. Xiaomi service centers cost 500-1000 ₽.

6.Problems with charger and cable

Incorrect charging is one of the most underappreciated causes of spontaneous reboots, and if Redmi 9 turns off and turns on when plugged into an outlet, it's the fault of:

• ⚡ Unoriginal cable (especially cheap no-name cable with AliExpress).
• 🔌 Damaged connector USB-C (oxidation, pollution, shattered contacts).
• 🔋 Unstable voltage in the network (jumps lead to power reset).
• 📵 Fast charging not supported by the phone (for example, the power supply on the phone) 65W Redmi 9, which supports maximum 18W).

How to check:

1. Connect your phone to another charger (preferably the original one from Xiaomi).
2. Try charging from power bank – if the reboots have stopped, the problem is in the socket or power supply.
3. Check the connector. USB-C for contamination (dust, debris) - clean gently with a toothpick.

If the phone only reboots when charging, but the other cable/block is working fine, the problem is solved, otherwise it may be necessary to replace the power controller on the motherboard.

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Never use chargers with higher voltages. 5V/2A for Redmi 9. Overloading on current can disable the power controller, and the phone will stop turning on at all.

7. Failures after Android Update

Android 10 Updates → 11 or MIUI 12 → 13 often break the stability of the Redmi 9.Typical complaints after an update:

• 🔄 Infinite Reboot (bootloop).
• 🛑 Hanging on the logo MI.
• 📱 Unintentional shutdown when unlocked.

If the problem occurs immediately after the update, try:

1. Reverse to the previous version via Fastboot (instructions on xiaomi.eu).
2. Clear the cache in Recovery (Wipe) → Wipe Cache).
3. Reset the settings (see Section 2).

If the phone does not load even in Recovery, only the firmware through the EDL-Mode (requires an authorized Xiaomi account and Mi Flash program).

8.External factors: cold, moisture, magnets

Sometimes Redmi 9 reboots due to the environmental impact of the following:

• ❄️ Low temperatures: at -10°C and below lithium-ion batteries are turned off.
• 💧 Moisture intrusion (even if the phone hasn't sunk, condensation can cause a circuit to close).
• 🧲 Strong magnetic fields (e.g., near speakers or induction plates).

If the phone is rebooted in the cold:

• Do not turn it on immediately after getting into heat - wait until it warms up to room temperature.
• Use a cover with insulation (for example, neoprene).
• Do not discharge the battery below 30% in cold weather.

When moisture is ingested:

1. Turn off your phone immediately.
2. Get it. SIM-card.
3. Place the device in a silica gel (or rice) bag for 24 to 48 hours.
4. Do not turn on until you make sure that the moisture has completely evaporated.

⚠️ Warning: If you get moisture, the phone turns on, but the screen flashes or the bands appear, it's a sign of corrosion of the contacts. The longer you delay repairs, the higher the chance that the fee will become unusable.

FAQ: Frequent questions about Redmi reboots 9