I ended up connecting to the Pi via the network with WinSCP logging in as
root with a password of
You will need to boot the Pi and then press F4 to exit emulation station.
When back in the terminal you will need to run
ifconfig to find the Pi’s IP address assuming you are connected to your home network.
Once the kick.rom is in I then changed the permissions of the whole emulators folder to allow the pi login access with the following lines:
sudo chown -R pi /opt/retropie/emulators/
sudo chgrp -R pi /opt/retropie/emulators/
… at least I think that’s what those lines are doing. Somebody a bit more versed in Linux will be able to tell you for sure.
Unfortunately I am still a novice and only getting about half an hour a night to play around with this.
Hope that helps.