Alas!! Ethernet is still slow after rebooting with FixRegions flag to true, in the /Volumes/EFI/EFI/Clover/config.plist
I have observed that kext files added to /Library/Extensions seem to have no effect, except as showing up as the kext location and version in the System Information > Ethernet Cards,
however without the IntelMausiEthernet present in /Volumes/EFI/EFI/Clover/kext/ the Ethernet does not work at all.
Intel l219V6 PCI Express Gigabit Ethernet:
Name: ethernet
Type: Ethernet Controller
Bus: PCI
Vendor ID: 0x8086
Device ID: 0x15be
Subsystem Vendor ID: 0x8086
Subsystem ID: 0x2074
Revision ID: 0x0030
BSD name: en0
Kext name: IntelMausiEthernet.2.5.0d0.kext
Location: /Library/Extensions/IntelMausiEthernet.2.5.0d0.kext
Version: 2.5.0d0
If the IntelMausiEthernet.kext is in both /System/Library/Extensions and /Library/Extensions,
the /Library/Extensions location & version will be displayed.
If only in /System/Library/Extensions, that location and version will be displayed.
I removed all the kext files I added to /Library/Extensions and the machine still boots and the network still runs (super slowly).
Any kext files I add to /Library/Extensions or /System/Library/Extensions are rejected when I run
sudo touch /System/Library/Extensions
sudo kextcache -i /
e.g.
Kext rejected du to improper filesystem permissions: <OSKext 0x7fb384c149c0 [0x7fff882108e0]> { URL = "file:///Library/Extensions/IntelMausiEthernet.2.5.0d0.kext/", ID = "com.insanelymac.IntelMausiEthernet" }
/System/Library/Extensions/IntelMausiEthernet.2.5.0d0.kext does not authenticate; omitting
As Ubuntu Ethernet is also very slow, I searched and found this bug report:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785171
Taking a clue from this, I tested booting a CentOS 7.6 LiveCD.
CentOS 7.6 uses the e1000e Intel Pro/1000 Network Driver - 3.2.6-k,
which is the same version e1000e Network Driver that Ubuntu 18.04 LiveCD uses,
but while Ubuntu Ethernet is super slow, just like macOS 10.14.5,
the CentOS 7.6 network is rock solid and could download the Clover EFI bootloader in 2 or 3 seconds,
whereas macOS or Ubuntu take 30-60 minutes, or fail entirely.
At least the CentOS test allays my fears that the hardware might be defective, and maybe it's not the BIOS settings either, since I don't change those when switching between CentOS and macOS or Ubuntu. Since the same driver version works in CentOS, that barely works in Ubuntu, perhaps focusing on the config.plist settings is the best approach? In case anyone is interested in taking a look at my EFI folder, I have zipped and attached it to this posting. I am very ignorant about the config.plist, .kext and .efi files, having gotten these mostly from @BlackHat13, here
https://www.tonymacx86.com/threads/cant-get-into-macos-installer-on-nuc8i7beh.277487/post-1962059
As a backup plan, I have ordered a TRENDnet USB Ethernet Dongle, which has an official macOS driver. With mouse, keyboard, bluetooth & ethernet, that would consume all the USB ports
