Official comment
The firmware update issue is separate from the audio issues; let's start there and make sure you're updated. First, format the USB drive to FAT (FAT32) with Master Boot Record. Then unzip the firmware to the root of the USB drive making sure no other firmware files exist. Also, if you downloaded the firmware with Safari, it may have corrupted the download on auto-unzip, so try another browser.
As for the audio, did it ever work before? If not, and you're on a Mac, you probably didn't install the drivers properly. Follow these instructions and uninstall / reinstall.
Also, check which mixer mode you have set in the RX2 utility menu on the hardware itself.