Unity in headless batch mode crashing in graphics initialisation in 5.6

I am trying to run Unity in headless batch mode with the following command, but it is not working; what am I doing wrong? `$UNITY -batchmode -nographics -buildLinux64Player build/main.linux64 -projectpath $(pwd) -logFile $LOG -quit` It is crashing on start up in InitializeEngineGraphics which implies that it is trying to initialise some graphics subsystem, despite the `-nographics`. This is on release 5.6.0xf3Linux. The system does *not* have a Unity-approved graphics card, but I thought that does not matter provided I say `-nographics`.