False positive. It was not the PERC controller that had a problem, but a faulty SAS HBA card that was stopping the server from booting. When the HBA card was removed, the server booted fine.Upgrading the HBA firmware, drivers and SAN firmware all together fixed the problem.Richard.  
Recently I used a maintenance window to upgrade my PowerEdge R630 . It has a SAS-RAID and PERC H730 mini controller. All the BIOS, firmware and driver updates worked fine. But the server would no longer boot into Windows (hung on the boot screen). Tried to repair windows, but repair does not see the Dell SAS disks. Eventually I downgraded the PERC firmware but it still would not boot. Had to find a spare disk, install Windows on that and start again. But as soon as I upgraded the PERC controller firmware, i can no longer boot again, same problem.   Is there a known issue with upgrading to 25.5.8 of the PERC H730 fimware?    
Upgrading PERC H730 (Mini) from version 25.5.2 to 25.5.8 stops windows booting.