Oppo
Reset System Settings auf Oppo
Over time, network profiles, display preferences and sound settings on an Oppo phone running ColorOS can end up in a state that causes odd behavior: WiFi that keeps dropping, a ringtone that will not change, or a wallpaper stuck from an old theme. Instead of wiping the whole device, ColorOS offers a dedicated option that resets only the configuration layer.
This function lives inside the backup tools of the system, even though its label sits next to the factory reset option. It restores network settings, display settings, sound settings, wallpaper and ringtones to their defaults, while leaving installed apps, photos, videos and documents untouched.
To use it, go to Settings ➔ Additional settings ➔ Back up and reset ➔ Erase all data (factory reset) ➔ Reset system settings only, then confirm by tapping Reset system settings only again.
After the reset, you need to reconnect to WiFi networks and re-enter passwords, re-pair Bluetooth devices, and choose a wallpaper and ringtone again. If the actual problem comes from a single app misbehaving, clearing that app's cache or data is usually faster and more targeted than resetting the whole system layer. If your phone has deeper issues like corrupted storage or persistent crashes, a full factory reset remains the more reliable fix.