Index: /trunk/src/VBox/Devices/PC/DevPcBios.cpp
===================================================================
--- /trunk/src/VBox/Devices/PC/DevPcBios.cpp	(revision 43749)
+++ /trunk/src/VBox/Devices/PC/DevPcBios.cpp	(revision 43750)
@@ -943,8 +943,8 @@
                               "HardDiskDevice\0"
                               "SataHardDiskDevice\0"
-                              "SataPrimaryMasterLUN\0"
-                              "SataPrimarySlaveLUN\0"
-                              "SataSecondaryMasterLUN\0"
-                              "SataSecondarySlaveLUN\0"
+                              "SataLUN1\0"
+                              "SataLUN2\0"
+                              "SataLUN3\0"
+                              "SataLUN4\0"
                               "FloppyDevice\0"
                               "DelayBoot\0"
@@ -1057,5 +1057,5 @@
     {
         static const char * const s_apszSataDisks[] =
-            { "SataPrimaryMasterLUN", "SataPrimarySlaveLUN", "SataSecondaryMasterLUN", "SataSecondarySlaveLUN" };
+            { "SataLUN1", "SataLUN2", "SataLUN3", "SataLUN4" };
         Assert(RT_ELEMENTS(s_apszSataDisks) == RT_ELEMENTS(pThis->iSataHDLUN));
         for (unsigned i = 0; i < RT_ELEMENTS(pThis->iSataHDLUN); i++)
Index: /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp
===================================================================
--- /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp	(revision 43749)
+++ /trunk/src/VBox/Main/src-client/ConsoleImpl2.cpp	(revision 43750)
@@ -464,4 +464,17 @@
         throw ConfigError("CFGMR3RemoveValue", vrc, pcszName);
 }
+/** Helper that finds out the next SATA port used
+ */
+static int GetNextUsedSataPort(int aSataPortUsed[30], int iBaseVal, int iSize)
+{
+    int iNextPortUsed = 30;
+    for (size_t j = 0; j < iSize; ++j)
+    {
+        if(aSataPortUsed[j] > iBaseVal &&
+           aSataPortUsed[j] <= iNextPortUsed)
+           iNextPortUsed = aSataPortUsed[j];
+    }
+    return iNextPortUsed;
+}
 
 #ifdef VBOX_WITH_PCI_PASSTHROUGH
@@ -1613,8 +1626,72 @@
                     if (!BusMgr->hasPCIDevice("ahci", 1))
                     {
+#define MAX_SATA_LUN_COUNT 4
+#define MAX_SATA_PORTS     30
+
+                        static const char * const s_apszBiosConfig[4] =
+                        { "SataLUN1", "SataLUN2", "SataLUN3", "SataLUN4" };
+
+                        int iPortNum = 0;
+                        uint32_t u32PortLUN[MAX_SATA_LUN_COUNT];
+                        uint32_t u32PortUsed[MAX_SATA_PORTS];
+                        uint32_t u32HDSataPortCount = 0;
+                        uint32_t u32MaxPortCount = MAX_SATA_LUN_COUNT;
+                        uint32_t u32NumAttachments = 0;
+                        DeviceType_T lType;
+                        com::SafeIfaceArray<IMediumAttachment> atts;
+
+                        /* init to max value */
+                        u32PortLUN[0] = MAX_SATA_PORTS;
+
                         if (pBiosCfg)
                         {
                             InsertConfigString(pBiosCfg, "SataHardDiskDevice", "ahci");
                         }
+
+
+                        hrc = pMachine->GetMediumAttachmentsOfController(controllerName.raw(),
+                                                            ComSafeArrayAsOutParam(atts));  H();
+                        u32NumAttachments = atts.size();
+                        if (u32NumAttachments > MAX_SATA_PORTS)
+                        {
+                            LogRel(("Number of Sata Port Attachments > Max=%d.\n", u32NumAttachments));
+                            u32NumAttachments =  MAX_SATA_PORTS;
+                        }
+
+                        /* find the relavant ports i.e Sata ports to which
+                         * HD is attached.
+                         */
+                        for (size_t j = 0; j < u32NumAttachments; ++j)
+                        {
+                            IMediumAttachment *pMediumAtt = atts[j];
+                            hrc = pMediumAtt->COMGETTER(Port)(&iPortNum);                   H();
+                            if(SUCCEEDED(hrc))
+                                hrc = pMediumAtt->COMGETTER(Type)(&lType);                    H();
+                                if(SUCCEEDED(hrc) && lType == DeviceType_HardDisk)
+                                {
+                                    /* find min port number used for HD */
+                                    if(iPortNum < u32PortLUN[0])
+                                        u32PortLUN[0] = iPortNum;
+                                    u32PortUsed[u32HDSataPortCount++] = iPortNum;
+                                    LogFlowFunc(("HD Sata port Count=%d\n", u32HDSataPortCount));
+                                }
+                        }
+
+
+                        /* Pick only the top 4 used HD Sata Ports as CMOS doesn't have space
+                         * to save details for every 30 ports
+                         */
+                        if (u32HDSataPortCount < MAX_SATA_LUN_COUNT)
+                            u32MaxPortCount = u32HDSataPortCount;
+                        for (size_t i = 1; i < u32MaxPortCount; i++)
+                            u32PortLUN[i] = GetNextUsedSataPort(u32PortUsed,
+                                                                u32PortLUN[i-1],
+                                                                u32HDSataPortCount);
+                        if (pBiosCfg)
+                            for (j = 0; j < u32MaxPortCount; j++)
+                            {
+                                InsertConfigInteger(pBiosCfg, s_apszBiosConfig[j], u32PortLUN[j]);
+                                LogFlowFunc(("Top %d ports = %s, %d\n", j, s_apszBiosConfig[j], u32PortLUN[j]));
+                            }
                     }