Sduva X was not starting for some intel gpu users. i released a custom build to fix it. I got the impression it also affected some intel+nvidia dual.
please, try this to get your discrete nvidia gpu to work:
1) Stop ES
/etc/init.d/S31emulationstation stop
2) create 99-nvidia.conf in /etc/X11/xorg.conf.d/
Section "Module"
Load "modesetting"
EndSection
Section "Device"
Identifier "nvidia"
Driver "nvidia"
BusID "1:0:0"
Option "AllowEmptyInitialConfiguration"
EndSection
3) Copy /etc/X11/xinit/xinitrc to /recalbox/system/.xinitrc
4) Add the following lines to /recalbox/system/.xinitrc inside the customisation block
xrandr --setprovideroutputsource modesetting NVIDIA-0
xrandr --auto
5) Start ES
/etc/init.d/S31emulationstation start
Please, send me the opengl string in system information.