Some users use third-party "Fastboot" tools or EDL (Emergency Download Mode) exploits to force an unlock.
Reboot your device into recovery mode by holding the Volume Up and Power buttons simultaneously. vivo u10 custom rom
This is the most difficult step. There is no official "Unlock Tool" for the U10. Some community-discovered commands like fastboot bbk unlock_vivo have been reported, but their success is highly inconsistent and depends on your specific firmware version. Some users use third-party "Fastboot" tools or EDL