Why Xiaomi Redmi Note 9 Pro is Rebooting and How to Fix It

If your Xiaomi Redmi Note 9 Pro started spontaneously restarting for no apparent reason, it’s not just annoying, it’s a signal of possible problems, and this behavior can be caused by software failures (for example, after the MIUI update) and hardware problems (battery wear, overheating of the Snapdragon 720G processor), in most cases, the problem can be fixed on your own without resorting to a service center.

But before you panic, you need to understand the root cause, like if you're rebooting only when you're charging, it could be the power supply or the cable, and if you turn off the phone in the cold, it's the normal lithium-ion battery reaction, and we've put together all the possible causes and solutions, from the simple (safe mode restart) to the radical (battery replacement).

1. Programmatic causes: MIUI and application failures

Most often, spontaneous reboots of the Redmi Note 9 Pro are associated with software conflicts.

• 🔄 Failed update MIUI — Especially if the phone is restarted after installing a new firmware version.
• 📱 Application failures – some programs (especially optimizers or launchers) can cause a critical system error.
• 🗑️ Fulled memory – if the device is less than 1 GB of free space, the system begins to work unstable.
• 🛠️ Damaged system files – for example, after incorrect root access or resetting settings.

The first thing you need to do is to start the phone in safe mode, and that's to help you understand if the third-party app is to blame.

1. Press the power button before the turn off menu appears.
2. Press and hold the "Switch off" option (a suggestion will appear to go to safe mode).
3. Confirm the action and wait for the reboot.

If the phone is stable in safe mode, the problem is in one of the installed applications. Uninstall recently added programs or perform a factory reset.

2.CPU overheating: why the Snapdragon 720G causes crashes

The Redmi Note 9 Pro is equipped with a Qualcomm Snapdragon 720G processor, which can overheat when under intense load. If the temperature of the chip exceeds 85-90 ° C, the system automatically restarts the device to prevent damage.

• 🎮 Long-term games (especially Genshin Impact, Call of Duty Mobile or more) PUBG).
• 🔥 Background processes – some applications (such as messengers or trackers) are constantly used CPU.
• ☀️ External factors: direct sunlight, use in a stuffy room or near heat sources.
• 🧊 Faulty thermopaste - over time it dries, worsening heat sink.

To check the temperature of the processor:

1. Install the AIDA64 app or CPU Monitor from Google Play.
2. Open the Temperature section and see the Snapdragon 720G.
3. If the temperature exceeds 70 ° C in plain – this is an alarming signal.

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If the phone gets hot while charging, try removing the case - it may block the heat sink. Also avoid using fast 33W charging while playing.

Decisions:

• 🛑 Close all background applications in Settings → Annexes → Launched.
• 🔧 Turn off auto-update apps on Google Play.
• ❄️ Use a cooling stand or fan (but don’t direct airflow directly into connectors!).
• 🔄 If the problem persists, reset the settings to factory (more on this below).

3. Battery problems: wear and bloating

The Redmi Note 9 Pro battery (5020 mAh) degrades over time, and after 300 to 500 charge cycles, its capacity decreases by 20 to 30 percent, resulting in:

• ⚡ Sudden shutdowns at a charge level of 20-30% (the system shows incorrect data).
• 🔄 Spontaneous reboots due to voltage surges.
• 💥 Battery bloating is dangerous! If the phone's case is deformed, turn it off immediately.

Check the status of the battery can be:

1. In the Settings menu → Battery → Battery status (if available).
2. Through the AccuBattery app (shows real capacity and wear).
3. Visually: Remove the back cover (if you can) and inspect the battery for bloating.

If the wear is more than 50% or the battery is bloated, it needs to be replaced. Self-replacement is possible, but requires care (risk of damage to the plumes). The cost of the original battery for the Redmi Note 9 Pro is about 1500-2500 ₽.

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Do not use a phone with a bloated battery! this can cause fire or damage to the motherboard.

4. Settings reset: when it really helps

If the software didn't work and there's no hardware problem (overheating, battery) -- try a factory reset, which will delete all the data, but return the system to its original state. Importantly, back up first!

Instructions:

1. Go to Settings → About Phone → Backup and Reset.
2. Select Settings Reset.
3. Confirm the action and wait for the completion (the phone will restart several times).

After discharge:

• 🔍 Do not restore data from the backup immediately – check the stability of the “clean” system.
• 📥 Install apps one at a time by watching your phone react.
• 🔄 If the reboots stopped, the problem was in the software.

Save contacts in Google Account | Copy photos and videos on PC | Record passwords from Wi-Fi and apps |Delete memory card (if any) | Check the charge level (at least 50%)

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If the reset did not help - the problem is most likely hardware (motherboard, power controller).

5. MIUI Update: How firmware affects stability

Xiaomi regularly releases updates for the Redmi Note 9 Pro, but sometimes they contain critical bugs that cause reboots. For example, in MIUI version 12.5.3, many users complained about spontaneous reboots when connecting to Wi-Fi.

What to do:

• 🔄 Reverse to the previous version MIUI (If you know the problem started after the update).
• 📥 Install the latest stable firmware manually via Fastboot or Recovery.
• 🛑 Turn off automatic updates in Settings → The phone. → Updating the system → Settings (⚙️) → Auto-update.

For hand-held firmware:

1. Download the official firmware from MIUI Download (select Redmi Note 9 Pro, joyeuse encoding).
2. Rename the file to update.zip and place it in the root of the phone’s memory.
3. Go to Settings → About Phone → System Update → Select a firmware file.

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If the phone is stuck on the MI logo after the upgrade, press Volume Up + Power for 10 seconds to go to Recovery and perform a reset.

6. Hardware malfunctions: what breaks most often

If none of the above methods worked, the problem lies in the hardware.The most vulnerable components of the Redmi Note 9 Pro:

Self-repairing these components is not recommended without experience, and there is a high risk of permanently disabling the phone. The average cost of a diagnostic at a service center is 500-1000. ₽.

7.When to contact the service: signs of serious breakdowns

There are situations where acting alone will only make the problem worse.

• 🔥 The phone is very warm in simple (even without a load).
• 💥 The body is deformed or divorces / artifacts appeared on the screen.
• ⚡ Reboots are accompanied by the smell of burning or smoke.
• 🔄 The phone does not turn on after spontaneous shutdown (even after charging).
• 📵 Symptoms appeared after falling or getting moisture.

In Moscow and St. Petersburg, the official repair of Xiaomi will cost 1500-5000 ₽ (Prices may vary in the regions before the visit:

• 📋 Write it down. IMEI phone (on the box or in the settings) → The phone).
• 🔋 Turn off the password/pattern lock (if the phone is switched on).
• 📄 Keep a check or a warranty card (if the warranty period has not expired).

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Official Xiaomi service centers offer a warranty of up to 6 months, and informal workshops can offer lower prices, but without warranties.

FAQ: Frequent questions about Redmi Note 9 Pro reboots