A used Vivo Y20 was sold to a new owner without being reset. After a factory reset from recovery mode, the phone asks for the previous owner's Google email/password (FRP Lock).
[Revised] How to use SP Flash tool to flash Mediatek firmware
The consensus: It is a powerful, time-saving tool for its supported range but is quickly becoming obsolete due to MediaTek’s continuous security patches.
Always ensure you download tools from reputable sources to avoid malware.