We have designed a custom board with i350 AM4 chip connected on PCIe x1 width in Gen1 speed.
We are using Arch linux 5.12.12 and igb drivers from the Linux package itself.
When we connect the ports (any or all) to another device and try to ping, i350 is resetting the link and dmesg appears as " igb: Adaptor reset". Ethernet port speed is 100 Mbps , Full duplex.
The reset appears periodically until ping command is stopped.
We are using EEPROM (copper and non management) with the image available from intel website.