Rpi model 3 b - server unexpectedly closed network connection

[akshaytimmalapur]

Hello, I am working on Rpi model 3 b and dropix flight controller for my project. I am setting up the Rpi board. I was able to establish SSH connection between laptop and Rpi. Basically I am following instructions given in this page:
http://ardupilot.org/dev/docs/raspberry ... vlink.html

When I try to disable the OS control of serial port using sudo raspi-config command, I get an error saying "Server unexpectedly closed network connection" when I try to reboot the board.

I checked online and it seems there is no proper solution given. I am new to using Rpi boards and hence any help in this matter is appreciated. Kindly help!!

Thanks

[mfa298]

I get an error saying "Server unexpectedly closed network connection" when I try to reboot the board.

That would be expected, when you reboot the board the network and any open processes get closed. Your SSH client (Putty?) sees that the connection has gone away and so reports it. As far as the client is concerned it was unexpected as it doesn't know what you've told the other end to do.