diff --git a/source/portable/NetworkInterface/Zynq/README.txt b/source/portable/NetworkInterface/Zynq/README.txt
index a1185c104..24541c737 100644
--- a/source/portable/NetworkInterface/Zynq/README.txt
+++ b/source/portable/NetworkInterface/Zynq/README.txt
@@ -40,3 +40,11 @@ It is obligatory to define:
 
 #define ipconfigZERO_COPY_RX_DRIVER               1
 #define ipconfigZERO_COPY_TX_DRIVER               1
+
+If using SDT drivers, it may be necessary to define certain link speed divisor values.
+This is to work around a driver issue where certain link speeds will not transmit any data
+without defining the values.  These macros can be defined in the FreeRTOSIPConfig.h
+For example, it may be necessary to define:
+
+#define XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV0 8
+#define XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV1 5
diff --git a/source/portable/NetworkInterface/Zynq/x_emacpsif_physpeed.c b/source/portable/NetworkInterface/Zynq/x_emacpsif_physpeed.c
index 6ea17fe92..ac9dcfcf0 100644
--- a/source/portable/NetworkInterface/Zynq/x_emacpsif_physpeed.c
+++ b/source/portable/NetworkInterface/Zynq/x_emacpsif_physpeed.c
@@ -500,19 +500,12 @@ unsigned configure_IEEE_phy_speed( XEmacPs * xemacpsp,
     return 0;
 }
 
-static void SetUpSLCRDivisors( int mac_baseaddr,
-                               int speed )
+static void WriteSLCRDivisors( int mac_baseaddr,
+                               u32 SlcrDiv0,
+                               u32 SlcrDiv1 )
 {
     volatile u32 slcrBaseAddress;
 
-    #ifndef PEEP
-        u32 SlcrDiv0 = 0;
-        u32 SlcrDiv1 = 0;
-        u32 SlcrTxClkCntrl;
-    #endif
-
-    *( volatile unsigned int * ) ( SLCR_UNLOCK_ADDR ) = SLCR_UNLOCK_KEY_VALUE;
-
     if( ( unsigned long ) mac_baseaddr == EMAC0_BASE_ADDRESS )
     {
         slcrBaseAddress = SLCR_GEM0_CLK_CTRL_ADDR;
@@ -522,7 +515,30 @@ static void SetUpSLCRDivisors( int mac_baseaddr,
         slcrBaseAddress = SLCR_GEM1_CLK_CTRL_ADDR;
     }
 
+    u32 SlcrTxClkCntrl = *( volatile unsigned int * ) ( slcrBaseAddress );
+    SlcrTxClkCntrl &= EMACPS_SLCR_DIV_MASK;
+    SlcrTxClkCntrl |= ( SlcrDiv1 << 20 );
+    SlcrTxClkCntrl |= ( SlcrDiv0 << 8 );
+    *( volatile unsigned int * ) ( slcrBaseAddress ) = SlcrTxClkCntrl;
+}
+
+static void SetUpSLCRDivisors( int mac_baseaddr,
+                               int speed )
+{
+    *( volatile unsigned int * ) ( SLCR_UNLOCK_ADDR ) = SLCR_UNLOCK_KEY_VALUE;
+
     #ifdef PEEP
+        volatile u32 slcrBaseAddress;
+
+        if( ( unsigned long ) mac_baseaddr == EMAC0_BASE_ADDRESS )
+        {
+            slcrBaseAddress = SLCR_GEM0_CLK_CTRL_ADDR;
+        }
+        else
+        {
+            slcrBaseAddress = SLCR_GEM1_CLK_CTRL_ADDR;
+        }
+
         if( speed == 1000 )
         {
             *( volatile unsigned int * ) ( slcrBaseAddress ) =
@@ -544,15 +560,17 @@ static void SetUpSLCRDivisors( int mac_baseaddr,
             if( ( unsigned long ) mac_baseaddr == EMAC0_BASE_ADDRESS )
             {
                 #ifdef XPAR_PS7_ETHERNET_0_ENET_SLCR_1000MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_1000MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_1000MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_1000MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_1000MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
             else
             {
                 #ifdef XPAR_PS7_ETHERNET_1_ENET_SLCR_1000MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_1000MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_1000MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_1000MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_1000MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
         }
@@ -561,15 +579,17 @@ static void SetUpSLCRDivisors( int mac_baseaddr,
             if( ( unsigned long ) mac_baseaddr == EMAC0_BASE_ADDRESS )
             {
                 #ifdef XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_100MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
             else
             {
                 #ifdef XPAR_PS7_ETHERNET_1_ENET_SLCR_100MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_100MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_100MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_100MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_100MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
         }
@@ -578,37 +598,24 @@ static void SetUpSLCRDivisors( int mac_baseaddr,
             if( ( unsigned long ) mac_baseaddr == EMAC0_BASE_ADDRESS )
             {
                 #ifdef XPAR_PS7_ETHERNET_0_ENET_SLCR_10MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_10MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_10MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_0_ENET_SLCR_10MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_0_ENET_SLCR_10MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
             else
             {
                 #ifdef XPAR_PS7_ETHERNET_1_ENET_SLCR_10MBPS_DIV0
-                    SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_10MBPS_DIV0;
-                    SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_10MBPS_DIV1;
+                    u32 SlcrDiv0 = XPAR_PS7_ETHERNET_1_ENET_SLCR_10MBPS_DIV0;
+                    u32 SlcrDiv1 = XPAR_PS7_ETHERNET_1_ENET_SLCR_10MBPS_DIV1;
+                    WriteSLCRDivisors( mac_baseaddr, SlcrDiv0, SlcrDiv1 );
                 #endif
             }
         }
-
-        /* SDT drivers should not write to the register */
-        #ifndef SDT
-            SlcrTxClkCntrl = *( volatile unsigned int * ) ( slcrBaseAddress );
-            SlcrTxClkCntrl &= EMACPS_SLCR_DIV_MASK;
-            SlcrTxClkCntrl |= ( SlcrDiv1 << 20 );
-            SlcrTxClkCntrl |= ( SlcrDiv0 << 8 );
-            *( volatile unsigned int * ) ( slcrBaseAddress ) = SlcrTxClkCntrl;
-        #else
-            ( void ) SlcrTxClkCntrl;
-            ( void ) SlcrDiv0;
-            ( void ) SlcrDiv1;
-            ( void ) slcrBaseAddress;
-        #endif
     #endif /* ifdef PEEP */
     *( volatile unsigned int * ) ( SLCR_LOCK_ADDR ) = SLCR_LOCK_KEY_VALUE;
 }
 
-
 unsigned link_speed;
 unsigned Phy_Setup( XEmacPs * xemacpsp )
 {