Before the update it was possible to set up an FTP server with this: https://play.google.com/store/apps/details?id=com.oxsoft.ftpserver and copy files to the box internal storage on local network.
Sadly after the Oreo update the server allows you to connect, but the home directory content is empty and also you can't copy any files. I've checked permissions, reinstalled the app, but no changes.
So now after the update how can you copy files onto the box internal storage?