The most frequent cause is a "Preloader" mismatch. The preloader is the first file the tool sends to initialize the hardware. Ensure you have the exact firmware for your model.
Using an outdated version of the tool that doesn't support your chipset. sp flash tool status ext ram exception
Ensure you have the latest MediaTek VCOM USB drivers installed via your Device Manager . Summary Checklist Potential Cause Wrong ROM Verify your device model and codename. Outdated DA Use a custom DA bin file for your chipset. Auth Security Run an MTK Auth Bypass tool first. Bad Connection Switch USB cables or ports. Are you still seeing the error after trying a custom DA? The most frequent cause is a "Preloader" mismatch