Your Xiaomi Redmi 9 suddenly starts to think about opening apps, hanging around during games, or reacting slowly to touch? This is a common problem that budget smartphone owners face after 1-2 years of use. The causes can be both software failures and physical wear and tear of components. In this article, we will examine all possible causes of brakes, from overloaded memory to battery degradation, and give step-by-step instructions for eliminating each of them.
It's important to understand: Redmi 9 It is based on the MediaTek Helio processor. G80 s 3/4 GB of RAM (depending on the modification), and over time these resources inevitably become insufficient for modern applications. 80% In some cases, you can solve the problem without replacing iron -- you can optimize the system quite well. Let's start with the simplest methods and gradually move on to more radical ones.
1. Diagnosis: how to determine the cause of brakes
Before you start "treatment", you need to identify the source of the problem. The brakes on Redmi 9 can manifest themselves in different ways:
- 🐢 Slow-motion animation when opening/closing applications;
- 🔄 Long loading of system menus (for example, Settings);
- 🎮 Lags in games, even those that used to work smoothly;
- 🔋 Sudden suspension at a charge level below 20%;
- 🌡️ Overheating the body during simple tasks.
Each symptom points to a cause, for example, slow motion animation is often associated with a lack of RAM, and low-charge hangings with a worn-out battery. To better identify the problem, follow the following steps:
- Open Settings → About Phone → MIUI version and tap 7 times on the kernel line to activate the developer mode.
- Go back to Settings → More → For developers and find the item Processor Statistics.
- Launch a problem app and watch the download schedule CPU/GPU. If the numbers are close 100% — iron-productivity problem.
Also check the battery status through the AccuBattery app (available on Google Play) if the capacity has dropped below 70% of the factory capacity (5020 mAh). → ~3,500 mAh, which is critical, the battery needs to be replaced.
2. Cleaning the system: remove garbage and cache
The most common cause of brakes is clogged memory, and even if you haven't installed new applications, the system accumulates gigabytes of unnecessary files over time: app cache, temporary data, remnants of deleted programs. 9 modestly 64/128 GB of memory is particularly critical.
Start by manually cleaning the cache:
- Go to Settings → Applications → Application Management.
- Sort the list by cache size (slip to three dots in the upper right corner).
- Select cache apps >500MB (e.g. YouTube, Facebook, Google Play Services) and click Clear Cache.
For deep cleaning, use the built-in Security app:
- 🧹 Open Security. → Cleanup → Deep cleaning;
- 🗑️ Select categories Unnecessary files, application cache, application residues;
- ⚠️ Do not clean the system cache manually – this can cause crashes!
Remove the cache of large applications|Clean up the downloads (Download folder)|Check the folder. DCIM photo-take|Disable Auto-Update Applications|Remove unused items APK-->
If you have brakes left after cleaning, move on to the next step, which is to optimize autoload. Many applications run with the system and consume resources in the background.
- Go to Settings. → Annexes → Autoboot.
- Turn off auto-run for instant messengers, social networks and games (except system services).
- Reboot the phone.
3. Performance optimization: settings for acceleration
Even after cleaning, Redmi 9 can slow down due to suboptimal system settings.
3.1. Cancel animation
Visual effects eat up to 15 percent of the output, to remove them:
- Activate the Developer Mode (as in Section 1).
- Go to For Developers → Scale of window animation and install No animation.
- Repeat for the items Size of animation transition and Duration of animation.
Transition to lightweight sheathing
MIUI It's known for being heavyweight. If your Redmi is heavyweight. 9 work MIUI 12/13, Try switching to Lite mode:
- Open the Settings. → Screen. → Lite mode.
- Turn on the option and restart the device.
This mode disables background processes and simplifies the interface, which gives performance up to 20%, but some features (such as Always-on Display) will become unavailable.
Restriction of background activity
By default, MIUI allows applications to run in the background without restrictions.
- Go to Settings → Battery and Performance → Battery Management.
- Select Application Selection and set the Background Activity Limit mode for all programs.
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If after disabling animation, the phone began to look “broken”, return the settings to the 1x — It is a compromise between speed and appearance.
4. Update firmware and roll back to stable version
Brakes often appear after updates MIUI. The manufacturer releases patches regularly, but some of them contain errors that lead to memory leaks or overheating of the processor:
Check the current version
Find out your version of the firmware:
Settings → The phone. → Version. MIUIIf the Global Stable version is, MIUI 14.0.2) -- it shouldn't be a problem. If you have a Beta or a Developer, it could be a problem.
Manual update
Sometimes the automatic update gets stuck to force it to update:
- Download the latest stable firmware for Redmi 9 from Xiaomi’s official website (select the Lancelot model for the global version).
- Move the file to the root of the phone’s memory (not to folders!).
- Go to Settings. → The phone. → Update the system and tap on three points → Select a firmware file.
⚠️ Warning: If the phone stopped turning on after the upgrade, don't panic.Plug it into a charger for 30 minutes - often this helps to restore work after a firmware failure.
Recoil on the previous version
If the lags came up after the update, you can return the old firmware.
- Download the correct version MIUI (for example, MIUI 13.0.5. if the brakes have started on 14.0.2).
- Rename the file to update.zip and place it in the root of the memory.
- Press Volume Up + Power to enter Recovery.
- Select Install update.zip and confirm the rollback.
After rollback, perform a reset (Wipe data in Recovery), otherwise there may be conflicts of system files.
5. Hardware problems: battery, overheating, memory
If the software didn't work, the brakes were caused by hardware, and let's look at the three most common hardware problems Redmi 9 has.
Wear of the battery
Lithium polymer batteries degrade over time, and after 300 to 500 charging cycles, the Redmi 9's capacity can drop to 60 to 70 percent of its original capacity.
- 🔋 The phone turns off at 20-30% charge;
- 🐢 Strong brakes at battery level < 15%;
- 🔥 Overheating during charging.
Check the battery status through AccuBattery or enter the following command in the engineering menu:
##4636##In Battery information, look at Battery Health if it shows Poor or capacity. < 3,500 mAh, the battery needs to be replaced.
Processor overheating
MediaTek Helio G80 Prone to overheating, especially under high loads:
| Mode of work | Normal temperature (°C) | Critical temperature (°C) |
|---|---|---|
| Simple (screen off) | 30–35 | >45 |
| Normal use (social networks, messengers) | 35–45 | >50 |
| Games/video editing | 45–60 | >65 |
| Charging. | 35–50 | >55 |
If the temperature is higher than normal:
- 🧊 Remove the cover (it can block the heat sink);
- 🔄 Close all background applications;
- 🛠️ Blow the charger connector with compressed air (dust worsens heat exchange).
⚠️ Warning: If the phone is heated to 70°C and above, this can lead to detachment of the battery or damage to the motherboard, in which case immediately turn off the device and contact the service.
Memory malfunction (eMMC)
Redmi 9 is equipped with built-in memory eMMC 5.1, which wears out over time.
- 💾 Hanging when writing/reading files;
- 🔄 Self-involved reboots;
- 📱 Errors in the installation of applications (INSTALL_FAILED_INSUFFICIENT_STORAGE).
The state of memory can be checked through AIDA64 (storage → If the Reallocated Sector Count is above 10, it's a signal that the memory is about to fail, and if it's a replacement, it's only going to help.
6 Radical methods: resetting, flashing, iron replacement
If none of these things worked, it's time to consider extreme measures, which take longer and sometimes more money, but are guaranteed to solve the problem.
6.1 Hard Reset (Hard Reset)
This will delete all the data, but it will bring the phone back to the factory state.
- Create a backup through Settings → Additional → Backup and Reset.
- Go to Settings → About the phone → Reset settings.
- Choose Delete all data and confirm.
After reset, don't restore data from the backup, which can bring back old errors. Install the applications again.
6.2 Flashing through Fastboot
If the system files are damaged, a complete flashing will help.
- Download Mi Flash Tool and Fastboot firmware for Redmi 9 (lancelot_global_images).
- Turn off the phone and press Volume Down + Power to log into the Fastboot.
- Connect the device to your PC and start the Mi Flash Tool.
- Select the downloaded firmware and press Flash.
⚠️ Warning: Do not turn off your phone while you are firmware! this can cause the device to blink (completely inoperable.
Replacement of the battery or motherboard
If the problem is physical wear, only repairs remain:
- 🔋 Replacement of the battery (cost: 1,500–2,500) ₽);
- 🖥️ Replacement of eMMC memory (only in the service center, price: 3000-5000) ₽);
- 🔧 Cleaning from dust and replacing thermopaste (relevant in overheating).
For Redmi 9, it is better to choose original parts - non-original batteries can swell or quickly fail.
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If the phone brakes even after it's reset and flashed, the problem is the hardware, and 90 percent of the time, the battery or the memory is to blame.
7. Alternative solutions: custom firmware and root
For advanced users, there are ways to get the best performance out of the Redmi 9, but they require technical skills.
Installation of custom firmware
Firmware like LineageOS or Pixel Experience lacks a “heavy” interface MIUI They work faster, though:
- ✅ Pluses: +30% of the performance, no advertising in the MIUI;
- ❌ Cons: loss of warranty, possible camera bugs/NFC.
Installation instructions:
- Unlock the bootloader through the Mi Unlock Tool.
- Install TWRP Recovery for Redmi 9.
- Download custom firmware (such as LineageOS 20) and download it through TWRP.
7.2. Obtaining root rights
Root gives you complete control of the system, allowing you to:
- 🚀 Remove system applications (bloatware);
- ⚡ Optimize the processor core;
- 🗑️ Clean the cache manually.
To obtain root:
- Install Magisk via TWRP.
- Sweep the patch. Magisk.zip.
- Reboot the phone.