Download the "Depth Testing" APK from Oppo’s official community. Install it, open the app, and apply for unlock. If approved, the phone reboots to fastboot, then you use: fastboot flashing unlock (Not fastboot oem unlock )
If Fastboot fails, try entering Recovery Mode by holding Power and Volume Down to perform a factory reset.
Oppo has different authentication servers for China ROM (ColorOS CN) and Global ROM (ColorOS IN/EU/APAC). If you bought a Chinese Oppo phone (e.g., Find X6 Pro CN) but flashed a Global ROM, the serial number database on the phone mismatches the regional server. The unlock verify process will fail because the token was requested from the wrong region.
fastboot flashing lock Then reboot to bootloader and retry the official unlock process.
Before your phone can even process cryptographic handshakes, internal developer flags must be properly aligned. If you can still boot into ColorOS, verify these settings:
Wait for the official "Approved" status (this can take up to an hour or a few days).
The error message is a critical security rejection thrown by an OPPO device's bootloader when an unauthorized attempt is made to unlock it. This specific error occurs because the device's unique hardware serial number or IMEI does not match the cryptographic signature generated within the unlocking token or the fastboot command framework.
If the Deep Testing app fails repeatedly, your phone may be a carrier-locked unit or a demo unit. In this case, no online method works. You must:
But a new app sat in the corner. An icon that looked like an eye. The name under it:
Are you using a specific like UnlockTool or SP Flash Tool?