What many mistake for a "download link" is actually a hardware diagnostic shortcut:
firmware(dot)oppo-update(dot)com/f3/v80 – oppo f3 update 80 download link
Always download the Full OTA version (1.8 GB) to avoid installation errors. What many mistake for a "download link" is
Tip: Ensure your phone has at least 50% battery and is connected to a stable Wi-Fi network before starting. Technical Specifications for OPPO F3 consider these alternatives:
If you cannot find a working link or the installation keeps failing, consider these alternatives: