Unistall Realtek USB Ethernet Network Adapter
Check the Realtek site for the latest driver of your USB Ethernet adapter and download it. The driver zip file should contain an uninstall.zip. Unzip this also and double-click the resulting uninstall.command file. Enter the admin (root) password and reboot your Mac.

Using an uninstaller provided with the driver installer is recommended.

Provided it's a RTL8153 chip you can also pour the following content into a uninstall.command file and execute it:

#!/bin/sh
. /etc/rc.common

echo "                                                                  "
echo "Please type the password of \"root\" to Uninstall ..."
FROM=`dirname "$0"`

echo "Removing Apple USB Ethernet Driver..."

sudo kextunload /System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/AppleRTL815X*.kext
sudo kextunload /Library/Extensions/AppleRTL815X*.kext

sudo rm -rf /System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/AppleRTL815X*.kext
sudo rm -rf /Library/Extensions/AppleRTL815X*.kext

sudo touch /System/Library/Extensions/
sudo touch /Library/Extensions/

echo "Uninstall Complete."


Depending on your system version you have to disable SIP.

In Catalina you have to disable SIP in Recovery Mode first and mount the system volume read-write after rebooting: sudo mount -rw /. Additionally you have to chmod +x uninstall.command and add it to System Preferences > Security &amp; Privacy > Privacy > Full Disk Access. 

Enable SIP after uninstalling the driver!



If your kext has a different name (e.g. AppleUSBRealtek8153Patcher.kext) or paths have changed, you have to adjust it respectively in the file uninstall.command (e.g. AppleRTL815*.kext). Use at your own risk!