In SPD Upgrade Tool → Settings → Enable and uncheck “Check TE Status” if available (advanced options).
If the phone is just hanging on the logo and not completely dead, try a hard reset first: Power off the device. Hold to enter Fastboot Mode . vivo y1s 2015 flash file dead hang logo 100 te hot
Extract the Firmware: Download the Vivo Y1S Flash File and extract the contents using WinRAR or 7-Zip. You should see a "Scatter" file inside. In SPD Upgrade Tool → Settings → Enable