It IS possible to unroot by simply removing the files that were added: /system/app/SURoot.apk /system/xbin/busybox /system/xbin/su (also, the root process leaves a dirty copy of these same files in /data/local/. They are no longer used and can be deleted without consequence)
But that won't restore any changes that were made to the device by rooted programs. If a root program made changes to the audio, or build.prop, or any system files, then those will remain.
The only way to guarantee the device is back to a factory state is by flashing a factory firmware on the device. Currently, the only method for doing this is by using the unroot/unbrick
guide. And unfortunately, that program is produced by LG and only runs on MSWindows.
Originally Posted by 2GigayteSD
WINE only has support for things like OS library files. It has No support for device drivers, and because of this, it will never work for the purpose of connecting hardware.
As an alternative, I've tried using the LG software on a VirtualBox of MSWindows. I had all the software installed and it did not work in my testing.
In the end, my only solution was to borrow the MSWindows laptop of a relative and reset the firmware using their system.