Sorry for reviving an old thread but since Google brings this post up when trying to figure out how to update the Gracenote database, I thought I'd tack on what I've found.
The latest Gracenote databases can be found here for download:
https://content.subarunet.com/snet/business/service/forms/audio_downloads.htm
Extract to a FAT32 formatted USB drive and use the "Gracenote Database Update" function in the radio's settings. Hope it helps..
BD