I've solved in this way,
the instructions on this page are incomplete: https://support.arduino.cc/hc/en-us/articles/12370721200540-Configure-GIGA-R1-WiFi-for-Over-The-Air-OTA-uploads
At the end of step 2, it is necessary to open the serial console, as in step 3, and choose the formatting type from the Arduino.
In practice, if you simply follow the instructions and move on to step 3, the partition to host the temporary binary for flashing will NOT be created.