To install firmware on your MixAmp Pro please visit Here
Download the ASTRO Command Center. Once the ASTRO Command Center is downloaded, connect the MixAmp TR to your computer via the USB power cable.
Once connected, check to make sure the MixAMp TR is in PC Mode (Power button should be illuminating White). If the MixAmp TR is not in PC Mode, hold down the power button for 3-5 seconds or until the power button LED light changes from Red to White.
Once your MixAmp TR shows that it is connected, the ASTRO Command Center will prompt you to update the MixAmp TR to the latest version of the firmware.