(Smart Phone Flash Tool) is used for MediaTek-based Symphony devices. USB Driver:

is the most effective way to resolve persistent software issues like boot loops, "hang on logo" errors, or system performance lags

I connected the phone to my PC — nothing. No QDLoader port, no MTK preloader beep. Dead as a brick.

Power off your phone. Hold the Volume Down (or both volume) buttons and connect it to your PC via USB.