sun4v FMA Firmware Faults
By user9148476 on Dec 03, 2009
Prior to these fixes, "ferg.invalid" errors would result in FMA reporting the infamous "nosub" fault (FMD-8000-0W). And a DBU error wasn't reported at all, the user experience being a mysterious system crash/reset.
As the cases for these errors are better understood, expect the article text on http://sun.com/msg to have more details.