I'm running version 2.3.0 of the kext in macOS Sierra 10.12.4 on a Dell Optiplex 7040, with an Intel ethernet chipset that shows up as I219LM2, but is listed as "I219-LM" in Dell's specs for the hardware. No matter what I try it won't autoselect a speed over "100baseTX <full-duplex,flow-control>", and manually setting it to 1000baseT causes it to fail and never connect. The same ethernet cable works at full speed via a USB3 adapter.
I'm running version 2.3.0 of the kext in macOS Sierra 10.12.4 on a Dell Optiplex 7040, with an Intel ethernet chipset that shows up as I219LM2, but is listed as "I219-LM" in Dell's specs for the hardware. No matter what I try it won't autoselect a speed over "100baseTX <full-duplex,flow-control>", and manually setting it to 1000baseT causes it to fail and never connect. The same ethernet cable works at full speed via a USB3 adapter.