I think, you have a PATA drive, on an "extra-added" PATA port (965's do not have native PATA!!) I had the same problem (if that is yours too): Solaris DOES know the SATA/PATA controller, whereas GRUB does NOT! I solved it by buying a native SATA drive, installed Solaris on that, and there it goes.
The problem is that that the PATA is emulated, and GRUB does not like that, hence it does not find a device to boot from. Is there a JMicron controller? Is the drive attached to that? This message posted from opensolaris.org
