How to work with SD card partition?

[Porcinus]

Did you set the country for the WiFi?
If not : https://github.com/RetroPie/RetroPie-Setup/wiki/Wifi
'raspi-config' can be found in Retropie menu.
If this doesn't work, a possibility is a false contact on Compute Module.
I think Flavor did post a "how to" video about this but I don't know where it is on the forum :S