How to Downgrade Oneplus 9 & 9 Pro from Oxygen OS 12 open beta 1 to Stable Oxygen OS 11

OxygenOS 12 Developer Preview 2 

• System
  • Optimized the auto-brightness algorithm to adapt screen brightness to more scenes for a comfortable screen reading experience
  • Optimized the mistouch prevention algorithm for curved screens to reduce accidental touches
• New design
  • Added widgets that show key information of apps and provide instant access to functions
  • Optimized the page layout and the presentation of text and color to make key information stand out
• Convenience & efficiency
  • Added swiftly switch floated windows, make operation more convenient
• Games
  • Optimized the frame rate performance under heavy-used scenes
• Camera
  • Added the feature that supported customize the display order of camera mode
  • Optimized the zoom experience, make it zoom more smoothly
• Performance
  • Added the form of chart to display battery usage
  • Newly supported pre-loading the apps that frequently used, to switch them on quickly
  • Improved the response speed of turning on or off Wi-Fi, Bluetooth, Airplane mode, and NFC

1. The Camera does not support Xpan, and contains some stability issues
2. This version does not support scrolling screenshot
3. The icon of Bluetooth connection displays abnormally
4. The icon of charging displays abnormally
5. The Cloud Service is unavailable (India)
6. The Camera app does not contain Hasselblad elements
7. This version is not compatible with some third-party apps
8. The included Google Phone app does not feature call record functionality. This can be solved by updating the app in Play Store.
9. Three-finger swipe down gesture or three-finger long-press gesture after using the screen recorder. This can be overcome by pressing Power button and Volume Down button simultaneously instead to screenshot.