Keep your battery charged to at least 70% to prevent power failures during the process.
With your custom recovery ready and your files on your SD card, you are ready to install Android 7.1.2. Step-by-Step Flashing oppo f1s firmware download 712 work
Because official stock ROMs max out at Marshmallow, you will need a stable Android 7.1.2 Nougat custom ROM. What to Download Keep your battery charged to at least 70%