peut être la réponse ici :" Important Note: If you have an Onyx 820i, 1220i or 1620i and are connecting to a Mac, please make sure you are running the latest firmware. To check or update your firmware version, download and run the Updater file in the below .dmg. The latest firmware version (1.05.00129) resolves an issue where, in certain cases, the device may not enumerate properly when powered on and connected while the computer is booting or rebooting."