How to increase the brightness of the screen on Xiaomi Redmi 9T: from standard settings to hidden chips MIUI

The 6.53-inch Xiaomi Redmi 9T screen with a resolution of FHD+ (2340×1080) provides excellent detail, but factory brightness settings don’t always meet users’ expectations: a dim display in sunny weather, automatic backlight surges or, conversely, excessive brightness in the dark are typical complaints of owners. In this article, we will examine all possible ways to increase the brightness of the screen, including hidden MIUI functions, color calibration and even hardware limitations.

It's important to understand that the Redmi 9T has a maximum brightness of 400 nits (according to the manufacturer), which is lower than the flagship models (600-1000 nits). However, with software tricks, you can squeeze more out of the screen than the standard slider offers. We tested each method on MIUI 12.5-14 firmware and identified those that actually work without risk to the matrix.

If you have a problem when the screen spontaneously dims when the battery is low, it is energy-saving mode, turning it off will give +15-20% of brightness, and for those who are ready for experiments, we will tell you how to get around the limitations of MIUI through the engineering menu (no root rights!).

1. Basic brightness settings in MIUI

Start by checking the obvious: maybe the brightness slider just isn't optimally tuned. In Redmi 9T, backlighting is available in two ways:

• 📱 Through the notification panel: swipe down from top to bottom, find the brightness slider (usually to the right of the icons Wi-Fi/Bluetooth). If it's not there, tap the ⚙️ icon in the top right corner of the panel and add the element manually.
• ⚙️ Through settings, go to Settings → Display → Brightness. You can turn on automatic adjustment (adaptive brightness) or manually move the slider to the right stop.

Note that if the slider is locked 50 to 70 percent, it's likely that the power saving mode is activated to remove the restriction:

1. Open Settings → Battery and Performance.
2. Select Battery Mode and set High Performance (or Balanced if the first option is missing).
3. Return to the display settings – the brightness slider will become 100% active.

⚠️ Attention: When manually adjusting brightness for maximum battery life, you reduce battery life by 20 to 30 percent. If the battery is important, use adaptive brightness with adjustment "for yourself" (more on this below).

2. Adaptive brightness: how to make it work properly

The adaptive brightness feature in MIUI is often criticized for its inaccurate performance: the screen can be too dim during the day or blind at night, due to incorrect calibration of the light sensor, which can be corrected without third-party applications:

1. Activate adaptive brightness in Settings → Display → Brightness.
2. Go to Settings → Special Features → Improve Visibility → Adaptive Brightness Adjustment.
3. Turn on the option and move the slider to the “Brighter” position (or “Darker” if the screen is blinding).
4. To fine-tune your phone, tap the ⚙️ icon next to the slider and select "Scaling Reset." Then hold your phone under different light sources (sun, lamp, darkness) and the system will retrain in 5-10 minutes.

The critical feature of the Redmi 9T is that the light sensor is located at the top of the screen next to the front camera, and if it is hit by a shadow (for example, from a finger or a case), the adaptive brightness will not work correctly.

💡

If adaptive brightness is still unstable, try to calibrate the sensor manually: close it with your finger for 5 seconds, then sharply remove your finger. Repeat 3-4 times, this will reset the cache of illumination values.

3. Hidden MIUI settings: engineering menu and color calibration

MIUI has hidden parameters that allow you to increase the brightness beyond the standard limits, one of them is the engineering menu, which you can access without root rights.

To open the engineering menu:

1. Open the Phone app and enter the code: ##36446337###
2. Select Hardware Testing → Sensors → Light Sensor.
3. Check the current sensor values. If they're close to zero in normal light, the sensor is defective.

For manual brightness calibration (only for power users!):

1. In the engineering menu, select Display.
2. Find Max Brightness (or Backlight) and increase the value by 10-15% of the standard (usually 255). Do not exceed 270 - this can shorten the life of the matrix.

Another way is to adjust the color profile:

• 🎨 Go to Settings → Display → Color scheme.
• Select a “Saturated” or “Standard” profile (the “Soft” profile artificially darkens the screen).
• 🔍 Turn on the Automatic Color Adjustment option (if available) to remove the gray hue that visually reduces brightness.

⚠️ Attention: Changing the settings in the engineering menu is not officially supported by Xiaomi. If after editing artifacts appear on the screen (bands, flicker), reset the display settings to Settings → System → Reset settings → Reset the display settings.

4. Third-party applications for brightness control

If standard methods fail, you can use apps from Google Play that circumvent the limitations of MIUI, but require overlay permission or special features.

Top.-3 tested:

• 🌞 Lux Auto Brightness is the most accurate adaptive brightness control with the ability to manually calibrate the sensor, supports night mode and blue light filter.
• 🔦 Brightness Control – adds a brightness widget to the home screen and allows you to set the values above the system (up to 1000 nits virtually).
• 🛠️ Screen Adjust — for fine-tuning gamut and contrast, which visually increases brightness.

To give the app control over brightness:

1. Install one of the applications above.
2. Open Settings → Applications → Permissions Management → Special Access → Change system settings.
3. Find the installed application in the list and allow it to control brightness.

Example of Lux Auto Brightness setup:

Turn off standard adaptive brightness MIUI| Set minimum brightness at 10% | Set maximum brightness at 90% |Activate Subzero mode for precise calibration |Reset sensor calibration in Lux--> settings

⚠️ Warning: Some applications (e.g., Brightness Control) may conflict with MIUI and cause the screen to flicker. If you notice artifacts, remove the utility and restart the phone.

5. Hardware limitations: when software methods do not help

If neither method worked, the problem could be the hardware, and here are the typical iron causes of a dim screen:

• 🔋 Backlight wear: LED- The Redmi 9T matrix is designed to last 30,000-50,000 hours. In heavy use (e.g., constant maximum brightness) after 2-3 years, the backlight dims by 20-30%.
• 🔌 Display plume problems: If the screen dims when the phone is tilted or after falling, the plume contacts may break. This requires repair.
• 🌡️ Overheating: At temperatures above 40°C MIUI automatically reduces brightness to protect the matrix. Check the temperature in Settings → About Phone → System Status.
• 🔄 Non-original matrix: if the screen was changed, a cheap analogue with low maximum brightness (200-250 nits instead of 400) could be installed.

How to check for hardware malfunction:

1. Compare the brightness of your Redmi 9T to another device of the same model under the same conditions (e.g., at 100% brightness in a dark room).
2. Run a matrix test: in the engineering menu, select Display → Test Pattern. If you see spots or stripes on a monochromatic background (white, red, green), the matrix is damaged.
3. Check battery consumption: if at maximum brightness the energy consumption does not increase (in Settings → Battery → Battery use), the backlight does not work at full power.

If a hardware problem is confirmed, the solutions are:

💡

If the screen dims only when the battery is low (less than 15%), it is not a malfunction, but the function of the Ultra Battery Saver. Shuts down in Settings → Battery → Ultra Battery Saver.

6. Alternative solutions: filters, wallpapers and modes

If you can't get the brightness up, you can go another way, which is to visually improve the perception of the screen, and these methods won't replace physical illumination, but they will make the image clearer.

• 🖼️ Dark wallpaper with contrasting elements: white text appears brighter on a black background. Use wallpaper with AMOLED- optimization (even on the IPS- Redmi 9T screen this will work).
• 🌙 Night mode: Paradoxically, turning on a blue light filter (in Settings → Display → Night mode) can reduce eye strain and create the illusion of greater brightness.
• 🔍 Enlarge font: Large text is easier to read when backlighting is low. Configure in Settings → Display → Text size.
• 🎯 High contrast mode: in Settings → Special features → Improve visibility, turn on "High contrast." This will make the colors richer.

For readers, the Xiaomi Reader app (or Google Play Books) has a separate brightness setting that works independently of the system setting, setting it 20 to 30 percent higher than the basic settings.

If you use your phone often outside, consider purchasing anti-reflective glass with a polarizing filter, which does not increase brightness, but reduces reflections, which improves visibility in the sun, starting at 300 ₽.

7. Frequent errors and myths about screen brightness

There are a lot of "advice" going around that not only doesn't help, but it hurts the phone.

• ❌ "Exterminate the display plume with alcohol, brighten": it's dangerous! Alcohol can damage the insulation of the contacts. Use a lilaless wipe with a minimum amount of isopropyl alcohol (no more than 70%) to clean.
• ❌ "Set maximum gamut in the engineering menu": it distorts colors and doesn't increase real brightness. The gamma is responsible for color balance, not backlighting.
• ❌ Turn off adaptive brightness, save battery: on the contrary, manually setting to maximum drains the battery faster. Adaptive brightness optimizes consumption.
• ❌ “Turn your phone over to custom firmware will be brighter”: most custom firmware (like LineageOS) don’t support the correct backlighting on Redmi 9T.

Another popular myth is that the brighter the battery goes down faster.

• When the brightness increases from 50% to 100%, the energy consumption grows by ~40%, not 2 times.
• At brightness below 30%, the screen enters an energy-saving mode where consumption is reduced disproportionately.
• The background color is stronger than brightness: black background (AMOLED-mode) saves up to 15% of charge even on the IPS-screen.

💡

To check the actual screen consumption, install the AccuBattery app and analyze the discharge schedule at different brightness levels.

FAQ: Answers to Frequent Questions