Hi @jcai ,
I am not sure about this one.. If a higher kernel version is required and the existing driver does not actually work, then maybe it is not a big surprise! 🙂
the kernel module is in the build, as specified in the config file here : https://gitlab.com/voxl-public/system-image-build/qrb5165-kernel/-/blob/qrb5165-ubun1.0-14.1a/arch/arm64/configs/vendor/kona-perf_defconfig#L328
Some info about the driver : https://gitlab.com/voxl-public/system-image-build/qrb5165-kernel/-/blob/qrb5165-ubun1.0-14.1a/arch/arm64/boot/dts/vendor/bindings/net/microchip,lan78xx.txt
You could try to pull source code from updated driver for this device from a newer kernel, drop it into the voxl2 kernel build and build the kernel with new driver. I think some users on this forum were able to do something similar with another device (not ethernet adapter).
Maybe try another ethernet adapter? 🙂
For example,
voxl2-mini:/$ lsusb -t
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 10000M
    |__ Port 1: Dev 2, If 0, Class=Vendor Specific Class, Driver=ax88179_178a, 5000M
voxl2-mini:/$ ethtool eth0
Settings for eth0:
	Supported ports: [ TP MII ]
	Supported link modes:   10baseT/Half 10baseT/Full 
	                        100baseT/Half 100baseT/Full 
	                        1000baseT/Half 1000baseT/Full 
	...
	Speed: 1000Mb/s
	Duplex: Full
	...
voxl2-mini:/$ iperf -c <my desktop machine ip>
------------------------------------------------------------
Client connecting to <my desktop machine ip>, TCP port 5001
TCP window size: 85.0 KByte (default)
------------------------------------------------------------
[  3] local <my voxl2 local ip> port 52708 connected with <my desktop machine ip> port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec   339 MBytes   284 Mbits/sec
Did not quite get 1 gig (about 300Mbit/s), maybe there is a bottleneck somewhere, but maybe that will work for you..
Alex