The Oppo A9 2020 (models CPH1937, CPH1983) has reached end-of-life status, with ColorOS 11.1 based on Android 11 serving as its final official firmware. Users can update via the system settings, while unbricking or fixing boot loops requires flashing the .OFP firmware file via PC using Qualcomm-specific tools. More information is available on the Oppo Community.
If you’re still using this phone, the latest CPH1937_11_F.37 (or your region’s equivalent) is the most stable. Just debloat using ADB, and you’ve got a reliable backup phone. Oppo A9 2020 Firmware
If you don’t trust online sources, an authorized Oppo service center can flash the official firmware for free or a nominal fee. The Oppo A9 2020 (models CPH1937, CPH1983) has