Use this guide at your own risk. The author is not responsible for bricked devices.
In the command prompt, type the following command to temporarily boot the recovery (recommended for testing first): fastboot boot twrp.img (Replace "twrp.img" with the actual filename of your download). twrp vivo y71 full
Connect the device to the PC via USB. Open a command prompt in the platform-tools directory and execute: Use this guide at your own risk
Inside the temporary TWRP: