ISP Tool V4.20.exe is a specific utility primarily used for firmware upgrades Growatt solar inverters , such as the Growatt SPF5000ES
While most common for Growatt inverters, "ISP Tool" (In-System Programming Tool) is a generic name for several different utilities: Growatt SPF5000ES Firmware Upgrade - Greenrich Isp Tool V4.20.exe
ISP Tool V4.20.exe is a Windows-based executable used for In-System Programming (ISP). Unlike traditional programming that requires removing a chip from a circuit board, ISP allows you to update the firmware or software of a microcontroller while it is still soldered into the device. ISP Tool V4
But Elias has a folder on his desktop, unassumingly named "Tools." Buried deep within it, past three subfolders, sits Isp Tool V4.20.exe. Do not use ISP/firmware tools to circumvent lawful
Detailed PDF guides for using the tool are available from suppliers like Marcels Solar specific button sequence