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Curbox

Grayscale Filter

Grayscale Filter turns your screen black and white when you open a chosen app. Color is one of the main reasons apps feel exciting and hard to put down — removing it makes them feel dull in a helpful way.

Setting Up Shizuku

The Grayscale Filter Setup screen showing an empty state and a Shizuku Permission Required card with a Grant Permission button The Shizuku Permission Required card appears until you complete the setup below.

Shizuku is a free Android app that gives Curbox the special permission needed to apply the grayscale effect. Setting up Shizuku is a one-time process — once done, it works for all features that need it.

  1. Install Shizuku Download Shizuku from the Play Store or from its GitHub releases page.

  2. Activate Shizuku Open Shizuku and follow its setup instructions. If you are on Android 11 or higher, you can activate it using Wireless Debugging — no computer needed.

  3. Grant permission to Curbox Open Curbox, tap Reducers, then tap Grayscale Filter. You will see a Shizuku Permission Required card. Tap Grant Permission and approve the popup.

Granting Permission Without Shizuku

If you prefer not to install Shizuku, you can grant the android.permission.WRITE_SECURE_SETTINGS permission directly using ADB (Android Debug Bridge) from a computer.

  1. Enable Developer Options on your phone Go to Settings → About phone and tap Build number seven times until you see “You are now a developer.”

  2. Enable USB Debugging Go to Settings → Developer options and turn on USB Debugging.

  3. Connect your phone to a computer Use a USB cable to connect your Android device to your computer.

  4. Install ADB on your computer If you don’t have ADB installed, download the Android SDK Platform Tools from the Android developer site and add it to your system PATH.

  5. Verify the connection Open a terminal or command prompt and run:

    adb devices

    Your device should appear in the list. If prompted on your phone, tap Allow to authorize the connection.

  6. Grant the permission Run the following command, replacing com.curbox with Curbox’s actual package name if different:

    adb shell pm grant neth.iecal.curbox android.permission.WRITE_SECURE_SETTINGS

  7. Verify in Curbox Open Curbox and navigate to Reducers → Grayscale Filter. The permission prompt should be gone and the feature should be ready to use.

Creating a Grayscale Group

Once Shizuku permission is granted, you can set up your groups.

  1. Tap the + button The + button is in the bottom right corner of the Grayscale Filter Setup screen.

  2. Name your group Type a name like “TikTok” or “Social Apps.”

  3. Select apps Choose the apps that should switch to grayscale when opened.

  4. Save Tap Done. The filter is active for those apps immediately.