F1s - Miui 8 Oppo

: The device bootloader must be unlocked to permit the installation of custom software.

: Charge your phone to at least 100% to prevent it from powering off mid-process. miui 8 oppo f1s

The installation follows a standard custom ROM flashing procedure: How do I want to upgrade my Oppo F1 s? : The device bootloader must be unlocked to

: Create a complete system backup via TWRP, as all data will be wiped. miui 8 oppo f1s

: Download a compatible MIUI 8 port for the Oppo F1s (often based on Android 6.0) and save it to your internal storage or an external SD card. How to Install MIUI 8 on Oppo F1s