Officially runs Android 5.1 (Lollipop) with ColorOS 3.0 .
If you'd like to move forward with the process, I can help you find specific resources. Let me know: firmware oppo f1s a1601
Over years of use, system partitions can become corrupted by stubborn malware or accumulated cache files. Flashing a "Stock ROM" wipes the slate clean, removing viruses that survive factory resets. Officially runs Android 5