I too have an issue with the Kext reporting the BIOS has disabled the NIC.
Seems like you can't have everything... if I do a chameleon CSM/BIOS boot the NIC works (at least it did when I used ALXEthernet.kext) while changing over to using Clover and UEFI boot I also changed to this kext and now I see this issue.
Toshiba C850 laptop for what its worth.
I'm wondering if perhaps the DSDT changes between a BIOS/CSM boot and a UEFI boot causing the NIC to be disabled.
So if you can do it try the non-UEFI boot.. maybe it will work.