He re-transferred the ROM file. This time, he took a deep breath. Install > Select Storage > Select Zip. Swipe to Confirm Flash.
Oppo has largely removed official methods for bootloader unlocking. Even if "OEM Unlocking" is visible in developer settings, it rarely functions as a gateway to full access on these devices. Community Hesitation: Oppo A9 Custom Rom
Because of these hardware restrictions, there is very little official support from major ROM communities . You will not find the listed on official sites for popular ROMs Complex Rooting: He re-transferred the ROM file