For users of the (models CPH1937, CPH1939, CPH1941), the custom ROM landscape is a complex balance between aging hardware and restrictive software policies. While the device remains a solid budget performer with its Snapdragon 665 chipset, official support has largely ended with ColorOS 11 . The Core Challenge: Bootloader Locking
However, with the correct vendor blobs extracted from the latest firmware and a modified device tree capable of handling the oppo_reserve structure, stable Android 11, 12, and 13 ROMs are technically feasible. oppo a9 2020 custom rom work