: Using the wrong firmware or interrupted flashing can "hard brick" a device, making it unresponsive.

: Use WinRAR or 7-Zip. Note : Many of these files are password-protected; the password is often the name of the website you downloaded it from.

: Most GSM tools are flagged as "False Positives" because they perform low-level system modifications. Use a dedicated "lab" PC or a Virtual Machine if possible.

I can then recommend the and steps for your specific device.