This HBA is not supported. HP has code embedded in the FW and Drivers that will not allow "non-HP" disks to be seen. We are facing the same issue with the 241 12Gb SAS HBA. We are actively engaged with HP on the 241 but not the 421. I would not expect much if any changes on the 421 at this point. It is slow going with the 241 as it stands and it is a newer card.