My problem sounds exactly like this one, which never got an answer: [image] Ethernet Shield only working if USB is plugged IDE 1.x Hello, I have a Hardware = MKR ZERO + Eth Shield, My software works fine between my PC + Hardware, only if arduino board is powered by usb t…

Ethernet Shield sketch not working when powered with USB DC adapter

stevekj October 29, 2021, 2:02am 5

Ok here is the shield installation:

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