@ian57
Ici j'ai trouvé une piste pour une rotation effective qui serait permanente :
https://raspberrypi.stackexchange.com/questions/101282/pi-4-screen-rotation-from-the-terminal
*"The "Screen Configuration" utility is indeed a GUI for XRandR. But the key is, it is actually editing a script that gets run at boot to make its changes persistent across reboots. Just calling XRandR, as Andrew Savinykh noted, will only apply the change until the next reboot.
The actual file that it modifies is /usr/share/dispsetup.sh. You can verify this by making a change, hitting the checkbox, then noting the change in the dispsetup.sh script.
Therefore, you can simply manually make your changes in dispsetup.sh (its just calling xrandr, so use man xrandr for syntax). Or you can copy the file from one Pi to another, etc."*
Il faudrait essayer d'accéder à ce fichier dispsetup.sh et voir comment l'éditer.