I am having the same issue. The file is written in the EEPROM of the Pluto as I can re-open it and see my changes. But upon reboot those files seem to be replaced with a copy of the unmodified version of the file. I'm also having an issue updating firmware as well by putting a copy of the updated firmware in this directory. It is supposed to see a new firmware and begin the update process. This too fails.
I don't see that anyone has found a resolution, so I was just asking again to be sure.
Thank you so much.
apparently the trick is to EJECT the Pluto based drive after editing the CONFIG file and writing to it. Once I did an EJECT it worked perfectly!
I suspected it to be a WINDOWS issue and this procedure made it work.