: Once enabled, navigate to Settings > More Settings > Developer options and toggle OEM unlocking and USB Debugging .
Here is the information regarding the (often referred to as the Auth Flash Tool or MTK/Bypass Loader). vivo v9 loader
Warning: This will void any remaining warranty and erase all user data. It also requires a specific version of the loader compatible with the V9’s anti-rollback protection. : Once enabled, navigate to Settings > More