Go to -> Version and tap Build Number 7 times until it says "You are now a developer."
If you have a variant that supports unlocking (like certain Chinese or Indian models), the general flow is: oppo A5 2020 auto recovery mode problem solution oppo a5 2020 twrp
common post-installation issues like stuck on the OPPO logo screen or bootloops. Go to -> Version and tap Build Number
Because modern Oppo devices use Android Verified Boot, flashing TWRP without disabling verification will cause a bootloop. Execute these commands in order: Flash the vbmeta image to disable verification flags: oppo a5 2020 twrp