Hi danger,
many thanks. I am still not sure if I got it right…
I have uploaded an Arduino sketch from the Arduio IDE using the USB cable. I have not tried bluetooth but I assume it will not work (fine for me).
From your post I understand that I can upload the default programs just from the Arduino IDE without “Reset Default Program” in Makeblock.
However, I just wanted to use Makeblock again to play with some scratch examples, and this does not work without an USB cable and a “Reset Default Program”. At least the code upload with Bluetooth has not worked without this reset. Maybe the USB cable alone will do the job.
Anyway, this is a working way…many thanks for your help!