To update the firmware for the DM-RTA you need to reinstall the DM-RTA software which also contains the latest version of firmware. You can download the software/firmware for Windows (PC) or Mac from the Downloads section of the DM-RTA product page here.
To check the version of your currently installed DM RTA firmware select the Help drop down menu > choose About.
Before downloading and installing the new DM-RTA software/firmware you need to power up your DM RTA and connect it to your computer via the included USB cable. Uninstall the DM RTA software currently installed on your computer before installing the latest version.
Click here for installation instructions for Windows.
Click here for installation instructions for Mac.
Click here for information on how to connect AudioControl calibration microphones to the DM-RTA
Click here for a DM-RTA Checklist