If it can help someone, I've designed a RASA 8 ventilated dust cap to create and/or update dark/bias library without having to remove the dew shield and the camera.
Regards,
https://www.thingiverse.com/thing:6853706
Ventilated_Dust_Cap.JPEG
Regards,
https://www.thingiverse.com/thing:6853706
Ventilated_Dust_Cap.JPEG