I guess there is no kind of protection using the SmartRF Flash Programmer tool against picking the wrong .hex code.
I then managed to brick the CC Debugger itself by overwriting its flash memory. When I plug it into the USB socket, the LED no longer light and when starting the SmartRF Flash Programmer tool I see no chip listed at all. So, I cannot reflash it using this tool.
Is there a way to recover from such a situation or the CC Debugger is good to throw in the garbbage can and I would need to buy a new one at the high tag price of 52$?