12 Reasons Why Redmi Note 9 Pro Reboots on Its Own (and How to Fix It)

The Xiaomi Redmi Note 9 Pro’s spontaneous reboots are one of the most common problems faced by smartphone owners after 1.5 to 3 years of use. At first, the device can rarely “glut” — for example, restart once a week after prolonged use of the camera or games. But over time, the frequency of failures increases, and the phone starts to turn off 5 to 10 times a day, making it almost unusable for work.

80% of the time, it's a combination of software and hardware factors, from processor overheating to custom firmware conflicts, but there are also specific "diseases" of this particular model, such as degradation of the power controller or errors in the module. NFC, In this article, we will discuss all possible causes, from the simplest (which you can eliminate yourself) to those that require the intervention of a service center.

Important: If your Redmi Note 9 Pro only reboots when connected to a charge, the problem is almost certainly with the power controller or battery.

How to Know if Reboots Are Not the Norm: 5 Warning Signs

Not every reboot is a sign of a breakdown, like after an update. MIUI The phone can restart once, which is normal behavior, but if you see any of these signs, it's time to sound the alarm:

• 🔄 The smartphone is turned off and turned on for no apparent reason (not after a fall, not when the battery is discharged).
• 🔥 Reboots occur when heated (for example, during games or charging).
• 📉 The frequency of failures increases with time (first once a month, then daily).
• 🔌 Phone does not turn on after restart (forced rebate via Power is required) + Volume Up).
• 🚨 An error message appears before turning off (e.g., “There was an error in the com.android.phone app»).

If there's one thing that's right, read on, and we've put together a quick checklist to help narrow down the possible causes.

Check the temperature of the body (overheating?)

Run your phone in Safe Mode (an app problem?)

Connect to another charger

Look at the error logs in Settings → The phone. → Error report

Update. MIUI last-minute-->

Critical: If the phone reboots every 5-10 minutes and gets too hot, turn it off immediately and don’t turn it on until the battery is replaced – this can cause the battery to bloat and damage the board.

Reason. №1: CPU overheating (and how to avoid it)

Redmi Note 9 Pro is equipped with Qualcomm Snapdragon processor 720G, It's prone to overheating under prolonged stress. Normal operating temperature is up to 45.°C, but if it rises above 50°C, the system forcibly restarts the device to prevent chip damage.

The main “provocateurs” of overheating:

• 🎮 Games (especially Genshin Impact, Call of Duty Mobile, PUBG high-set).
• 📷 Prolonged video shooting in 4K or night-time.
• 🔄 Background processes: synchronization of the cloud, application updates, work VPN.
• 🌡️ External factors: direct sunlight, use in the car in summer, covers with poor ventilation.

How to check the temperature:

1. Install the AIDA64 or CPU Monitor app.
2. Run a stress test (such as a game) and watch the temperature chart.
3. If the temperature is above 55°C is a critical indicator.

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To cool your phone quickly, turn it off, remove the case, and place it on a cold metal surface (like an aluminum can from the fridge).

If overheating occurs even in standby mode, two problems are possible:

1. The thermopaste is dry - it requires disassembly and replacement (in the service center).
2. The battery is swollen - it is urgent to replace!

Reason. №2: Firmware errors and conflicts MIUI

Redmi Note 9 Pro is especially sensitive to updates MIUI. Many users faced massive reboots after the release of versions MIUI 12.5 and MIUI 13 due to errors in the core of the system. e.g. 2021 after upgrading to MIUI 12.5.3 thousand devices began to “go into rebut” due to a bug in the driver Qualcomm.

How to check if the firmware is to blame:

• 📱 Go to Settings. → The phone. → Version. MIUI Check the relevance of the updates.
• 🔍 Check out the reviews on the forums (for example, 4PDA Mi Community – if other users complain about the same version, the problem is the firmware.
• 🛠️ Try to revert to the previous version (instruction below).

Firmware rollback instructions:

1. Download the stable version MIUI Redmi Note 9 Pro (codenamed Joyeuse) from Xiaomi.
2. Rename the file to update.zip and place it in the root of the phone’s memory.
3. Go to Settings. → The phone. → Update system, press three points → «Select a firmware file».
4. Select update.zip and wait for the process to be completed.

MIUI 12.5

MIUI 13

MIUI 14

Custom firmware (LineageOS, Pixel Experience, etc.)

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Attention! If the phone only reboots when connected to Wi-Fi or mobile network after the upgrade, the problem may be in modem firmware, in which case a complete flashing through Fastboot (instructions in the "Hardware reasons" section) will help.

Reason. №3: Application conflicts and viruses

About 30 percent of spontaneous reboots involve background applications that conflict with the system or consume too much resources.

• 🛡️ Antiviruses (e.g. Avast, 360 Security) – they block system processes).
• 🎵 Music players with aggressive optimization (e.g. Poweramp or other types of music) AIMP).
• 📱 Launchers (for example, Nova Launcher or Microsoft Launcher).
• 🔄 Automatic cleaning applications (Clean Master, CCleaner).

How to find the culprit:

1. Launch your phone in Safe Mode (press the power button) → long tap on "Switch off» → «Safe Mode»).
2. If the reboots have stopped, the problem is in one of the installed applications.
3. Remove suspicious programs, starting with the last ones installed.

If you suspect a virus:

1. Install Malwarebytes and scan the system.
2. Check the rights of the superuser (Settings) → Annexes → Management of rights → Administrator rights – there should be no unknown applications.
3. If nothing helps, reset your phone to factory settings (Settings) → Additionally. → Recovery and discharge).

Reason. №4: Battery problems (most dangerous case)

Battery Redmi Note 9 Pro (model) BM47, The capacity of 5020 mAh has an average lifespan of 2-3 years, after which its capacity drops to 60-70%, and internal resistance increases, which leads to a decrease in the capacity of the battery:

• 🔋 Sudden shutdowns at a charge level of 20-30% (although the indicator shows, for example, 40%).
• 🔥 Overheating when charging or loading.
• 💥 Bloating (if the phone case began to “blown up” or the screen rose – immediately turn off the device and do not use it!).

How to check the status of the battery:

1. Install AccuBattery and see the actual capacity (if it is below 3500 mAh – the battery is worn out).
2. Check the Settings. → Battery → Battery status (if it says “Replace battery” is a direct signal).
3. Inspect the case: if the back cover appeared "bubbles" or the screen "goes away" - the battery swelled.

Attention, if the battery is swelling:

⚠️ DO NOT try to open your phone or puncture your battery! Lithium polymer batteries can ignite if damaged. Take the device to a service center or dispose of it according to local regulations.

The cost of replacing the battery in the Redmi Note 9 Pro:

Reason. №5: Charging malfunctions (power controller, cable, unit)

If the Redmi Note 9 Pro reboots only while charging, the problem lies in one of three components:

1. Charging unit (especially if you use non-original or power above 33 watts).
2. Cable USB-C (damaged wires or oxidized contacts).
3. Power controller on the motherboard (a common problem after falls or moisture).

Diagnosis by step:

• 🔌 Try another charger (preferably the original Xiaomi on the back) 33W).
• 🔄 Try another cable (better with Quick Charge 4 support)+).
• 📱 Check the connector. USB-C on the phone – if it is wobbling or has oxidation, a replacement is required.
• 🔧 If nothing helps - the power controller is defective (the board needs repair).

Attention, if the phone reboots when charging and the connector warms up a lot. USB-C, It could be a sign of a short circuit:

⚠️ DO NOT use your phone before repair! A short circuit can disable not only the power controller, but also the processor, and cause a fire.

Reason. №6: Hardware breakdowns (memory, board, power button)

If all previous methods failed, the problem lies in the hardware, and here are the most common hardware reasons for the Redmi Note 9 Pro reboots:

If you suspect a hardware breakdown, do the following:

1. Check if there were any physical damage (falls, bumps, moisture).
2. Examine the phone for oxidation (green plaque on the connector contacts or under the lid).
3. If the phone doesn’t turn on after the reboot, try going to Fastboot (press the Power). + If you can, run your phone through the Mi Flash Tool.

Critical case: if the phone reboots and it emits a high-frequency squeak, it's a sign of a failure of the circuit board voltage converter.

⚠️ DO NOT TRY to turn the device on again! The squeak indicates a short circuit that could knock out the processor.

What to do if nothing helps: extreme measures

If you’ve tried all the methods, but the Redmi Note 9 Pro is still rebooting, there are three options left:

• 🔄 Full reset to factory settings (deletes all data, but sometimes helps with deep software failures).
• 🛠️ Fastboot flashing (if the problem is in the damaged system partition).
• 🏥 Diagnosis at the service center (if iron is to blame).

Instructions for flashing through Fastboot:

1. Download Mi Flash Tool and firmware for joyeuse (for example, from here).
2. Turn off your phone and press Power + Volume Down to log into Fastboot.
3. Connect your phone to your PC and start the Mi Flash Tool.
4. Select the downloaded firmware and press Flash.
5. Wait until the phone is finished (the phone will reboot automatically).

If the phone doesn’t turn on at all:

• Try charging it from another unit for 30 to 60 minutes.
• If there is no reaction, check if the emergency mode is working (press the Power). + Volume Up 10-15 seconds).
• If it doesn’t work, then you can use it to burn. PMIC chip).

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If the phone reboots even after it's completely reset and flashed, the problem is the hardware, and further attempts at repair without diagnosis can make the breakdown worse.

FAQ: Frequent questions about Redmi Note 9 Pro reboots