The 4.2.1.2 firmware for Dante AVIO adapters has been temporarily removed from the Dante Updater application. This is due to a bug that may cause problems when enrolled into Dante Director.
This issue was resolved in the Dante AVIO firmware update v4.2.3.5. If you're experiencing this behavior, please update your device to this firmware version (or later) using Dante Controller / Dante Updater.