Why Redmi 8 phone turns on and off: the main reasons
If your Xiaomi Redmi 8 starts spontaneously restarting in a loop, the problem can be a software failure or a hardware malfunction, which is most often experienced by owners after a device falls, moisture gets in or a failed MIUI update, but sometimes even a worn-out battery that no longer holds the charge stable is to blame.
The first thing to understand is that a cyclic reboot is not just a one-time system error, it's a signal of a major failure. The phone can turn on for 5-10 seconds (sometimes even loading the Redmi logo), and then shut down again. In some cases, the screen doesn't even catch fire — the device just vibrates and turns off. Let's look at all the possible causes and solutions.
Important: If the phone does not respond to charging or heats up when rebooting, this may indicate a short circuit in the board, in this situation, it is better to contact the service center immediately.
1. Battery check: the main culprit behind spontaneous shutdowns
The battery is the most vulnerable spot in the Redmi 8 after 2-3 years of use. Lithium polymer batteries degrade over time and their capacity drops. If the phone only turns on while charging or turns off when the cable is disconnected, the battery is almost certainly the problem.
How to check:
- 🔋 Connect your phone to charge and watch: if it works stably but shuts down without power, the battery is discharged to a critical level.
- 🔥 Check if the battery is swelling: gently press the back cover – if it is “playing” or there are gaps, the battery requires replacement.
- 📊 Use the AccuBattery app (if the phone is switched on for a while) to see the actual capacity. If it's below 70% of the factory capacity (4000 mAh), it's time to change it.
If the battery is swelling, do not try to charge or use it - it is dangerous to health. Lithium polymer batteries can ignite if damaged.
2. resetting to factory settings: a universal solution for software failures
If the phone even occasionally turns on and gives access to the menu, try making a Hard Reset, which will delete all the data, but return the system to its original state, often helps with crashes after updating MIUI or installing incompatible applications.
How to reset your settings:
- Turn off the phone (if it is on, hold the power button for 10+ seconds).
- Press Volume Up + Power and hold until the Mi logo appears.
- In the Recovery menu, select Wipe Data → Wipe All Data (manage by volume buttons, confirm by power button).
- After reset, select Reboot → Reboot to System.
Save important data on a PC or cloud|
Remember your Mi Account (linked email/phone)|
Charge your phone at least 50% |
Prepare. SIM-Wi-Fi card and password-->
⚠️ Warning: After resetting, the phone will require you to enter the details of the Mi Account that was previously linked.If you forgot the password, unlocking can take up to 72 hours (according to Xiaomi rules).
3. Update or flash MIUI: if the system is damaged
Sometimes cyclical reboots are caused by corrupting system files, which can happen after a failed air-to-air update or manual firmware, and in such cases, clean installation of MIUI via Fastboot helps.
Step-by-step:
- Download the official firmware for Redmi 8 (codenamed olive) from Xiaomi Firmware.
- Unpack the archive and install the Mi Flash Tool on your PC.
- Turn off the phone, press Volume Down + Power to enter Fastboot mode.
- Connect your phone to your PC and in the Mi Flash Tool, select the downloaded firmware. Press Flash.
If the firmware is interrupted, the phone can turn into a brick. USB-cable and do not pull the battery during the process.
What do you do if the firmware is frozen?
Checking the power button and the plumes
Mechanical damage is a common cause of spontaneous shutdowns. The power button in Redmi 8 can stick or, conversely, make poor contact with you over time, and the problem can lie in the battery or display plume that has gone away.
How to diagnose:
- 🔧 Carefully tap on the phone’s body near the power button – if it reacts (on/off), the micro-switch is to blame.
- 🔍 Light a flashlight in the charging connector: if there is moisture or oxidation inside, it can cause short circuits.
- 🛠️ If you disassemble the phone yourself, check the density of the plumes adjacent to the motherboard (especially the battery and display).
⚠️ Warning: If you've never taken a smartphone apart, it's best not to take risks - Redmi 8 plumes are very fragile.
5. Diagnosis of the motherboard: short circuits and overheating
If the phone heats up when it reboots or turns off with a characteristic click, the problem may be the motherboard.
- 🔥 Overheating of the processor (Snapdragon 439 in Redmi 8 is prone to this at high loads).
- ⚡ Short circuit in food chains (often after moisture is ingested).
- 💾 Damage to memory chips (eMMC or RAM).
It's almost impossible to fix the board yourself -- it requires a soldering station and experience, but you can do a primary diagnosis.
| Symptoms. | Probable cause | Decision |
|---|---|---|
| The phone turns on, but the screen blinks and goes off. | Problem with display plume or graphics chip | Replacement of a plume or chip soldering |
| Vibration when turned on, but the screen is black | Failure of the backlight or display module | Screen replacement |
| The phone is turned off when loaded (games, camera) | Processor overheating or cooling system malfunction | Cleaning from dust, replacing heat paste |
| Cyclical reset with vibration every 3-5 seconds | Short circuit in the food chain | Diagnostics in the service, replacement of components of the board |
💡
If the phone falls into the water, don't turn it on right away. Dry it in rice or silica gel for at least 24 hours, or better yet, take it to the service for ultrasonic cleaning.
Alternative methods: from charging to cooling
Sometimes the problem is solved in ways that are not obvious. Try these methods if none of the above has worked:
- 🔌 Change the charger: Use the original Xiaomi power supply (5V/2A). Cheap charging can cause voltage surges.
- ❄️ Refrigeration: Put your phone in the fridge (not in the freezer!) for 10 to 15 minutes. If it turns on after that, it's overheating.
- 🔄 Extraction SIM-Cards: Sometimes conflict with operator or damaged SIM Try turning on your phone without a card.
- 📴 Turning off all buttons: If the phone responds to random taps (such as in your pocket), block the buttons through Settings → Lock screen → Locking hardware buttons.
If the phone is turned on in Safe Mode, the problem is exactly in the software. Uninstall the recently installed apps or perform a reset.
💡
If the phone only turns on while charging, 90 percent of the time it's the battery, and if it doesn't turn on at all, it's the board or the plumes.
7. when there is only a service center
If you’ve tried all the techniques, but the Redmi 8 is still cyclically rebooting, it’s time to turn to the professionals.
- 💥 The phone fell from a height or was flooded.
- 🔥 On the board, blackened or bloated elements are visible.
- 📵 The phone is not defined by the computer in Fastboot or EDL.
- 🔄 The reboot cycle is accompanied by the smell of burning.
Cost of repair in the service:
| Type of repair | Approximate price (₽) |
|---|---|
| Battery replacement | 1 200 – 1 800 |
| Replacement of the power button | 800 – 1 500 |
| Diagnostics and ration of fees | 2 000 – 5 000 |
| Replacement of the display module | 2 500 – 4 000 |
⚠️ Warning: Unofficial services may install substandard parts. Contact Xiaomi Authorized Centers or Verified Workshops with a warranty.