In order to update an existing 350 QX to firmware 2.0, there are two options:
Option 1: Purchase the USB-Interface cable and complete the firmware installation yourself. This update is very easy to install, the software is compatible with both PC & MAC and is available HERE for FREE.
Option 2: For a service charge of $75 (plus shipping and handling), the service department at Horizon Hobby will complete the update for you and return the product once complete. Please go to our Service Center page to fill out a service request form.More information about how to complete the update is available in the USB-Interface cable instruction manual which can be seen here.