Huawei Y9 Prime STK-L21 User Guide
![Huawei Y9 Prime STK-L21 Smartphone manual cover](/images/QvovJMkWXJRZJVBJGviZTkDC/thumbs/thumb175x175.webp)
To take a screenshot, press and hold the Power button and Volume Down button simultaneously for a few seconds. The screen will flash, indicating a screenshot has been captured.
Go to Settings > About Phone. Tap on 'Build Number' seven times until you see a notification that Developer Options have been enabled.
First, ensure the device is charged by connecting it to a power source. If it doesn't turn on, try performing a soft reset by holding the Power button for about 10 seconds.
Reduce screen brightness, close unused apps, disable unnecessary notifications, and use Battery Saver mode in Settings to improve battery life.
Go to Settings > Apps & Notifications > Apps. Select the app you want to clear cache for, then tap on 'Storage' and select 'Clear Cache'.
Connect the phone to the computer using a USB cable. On the phone, select 'File Transfer' from the USB options. Your device should appear on the computer for file transfer.
Go to Settings > System & Updates > Reset > Factory Data Reset. Follow the on-screen instructions to complete the process. Ensure you back up your data first.
Go to Settings > System & Updates > Software Update. Tap 'Check for Updates' and if an update is available, follow the prompts to download and install it.
Clear the camera app cache by going to Settings > Apps & Notifications > Apps. Find the Camera app, tap on 'Storage', and select 'Clear Cache'. Restart the phone if needed.
Go to Settings > Display & Brightness > Dark Mode. Toggle the switch to enable dark mode across the system and supported apps.