As we all know Android is open-source, so it's every users right to modify/ install custom ROM on their devices. Custom ROM development also helps to figure out problems in stock ROM too. But vivo is not allowing/providing official bootloader unlock tool and releasing kernel sources which are essential for installing a ROM which is unfair and is not tolerable. So vivo should release bootloader unlock tool and kernel sources ASAP as it will harm Company's reputation and its users.