Hello @mtd
Yep, one needs to modify its /boot/recalbox-user-config.txt by adding:
dtoverlay=vc4-kms-dsi-7inchand /boot/cmdline.txt with:
video=DSI-1:800x480@60,rotate=180at the end of the existing line.
I think I will create a new "case" to automate those 2 settings.