"No device found on COM" in Arduino with Shield [SOLVED]

Development Tools IDE 1.x
1

Dear All,
if I use IDE 1.8.10 and an Arduino Due, I have no problem with upload my firmware in "programming port" or "native usb port". But if I connect a shield to Arduino Due, I can't program because I receive the message: "No device found on COMx". In my project Arduino Due shares with the Shield: GND and some communication pins (SPI, I2C, ...). But Arduino Due does not provide power to the Shield.
I also tried to supply 8V in Vin and program Arduino Due with the USB port but the problem is not solved.

Please, has anyone had the same problem or can you help me?
Thank you

Regards,
Donatello

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(deleted)

3

The solution is: do not use RX and TX (respectively digital port 0 and 1), leave these pins floating.