How do you completely erase ESP32 flash chip using Flash Download Tool? This has been tricky for a long time (LONG time, especially in case of the ESP8266). This has been made simple in the latest version of the Flash Download Tool.
Get the Flash Download Tool v.3.6.x or higher
This version of the Flash Download Tool comes with a simple "Erase" button. This lets you completely erase ESP32 flash memory.
This is something you should do every time you get a fresh ESP module and plan to run your own custom firmware on it.
Note that we are not providing a link to the new Download Tool because the link changes rather frequently. You can find the Download Tool on Espressif's official website. The one download tool supports all of Espressif's chips (ESP8266 and variants as well).
A little note...
It would probably be a good idea to select the flash size manually rather than just rely on the automatic size detection. Murphy loves ESP developers most!