virtualhere seems to be commercialware - $40?? Never tried it. "usbip" is Linux software and can be compiled, a kernel module is needed.
here are some basic instructions for usbip that I found with google:
https://www.howtoforge.com/how-to-se...h-debian-lenny
here is my attempt to compile kernel modules:
https://www.mobileread.com/forums/sho...43&postcount=5
make sure the kernel modules you make are the same version as your firmware -
"uname -r"
Have you tried looking into the preferences of Calibre? It looks like the folder option is just an option of the share button?
I've not tried any of this, please experiment and let us know how you make out?