Because this is a downgrade, the process involves installing the rollback package via the recovery menu. Step 1: Download the Exclusive Rollback Package

: Certain legacy tools, root applications, or custom ROM procedures require specific older baseband versions to unlock the bootloader seamlessly. Comparing OPPO A9 2020 Core OS Versions

For the OPPO A9 2020 Go to product viewer dialog for this item.

For advanced users, the ColorOS community forums often host links to rollback packages.

The OPPO A9 2020 was launched in September 2019 as a mid-range smartphone with standout features including a 48 MP quad-camera setup, a large 5000 mAh battery, and a 6.5-inch display. It originally shipped with ColorOS 6, which was based on Android 9 Pie. Over its lifecycle, the device received major updates, culminating in ColorOS 11.1 based on Android 11.

Download the specific rollback .zip file from the link above. Move to Storage:

If you choose to proceed with a downgrade at a service centre, keep these points in mind:

Back up all essential photos, contacts, and personal data to a computer or an external cloud storage drive.

Is this package truly "exclusive"? Not really. These files are official Oppo releases meant for Service Centers. However, they are incredibly hard to find online because Oppo removes them frequently to prevent users from bricking their devices.

usually carries model numbers like or CPH1939 ). Flashing a firmware file built for a different model variant will brick your device. Step 2: Sourcing the "Exclusive" Rollback Package