diff --git a/features/netsocket/emac-drivers/TARGET_STM/mbed_lib.json b/features/netsocket/emac-drivers/TARGET_STM/mbed_lib.json
index 90635673c7..7f85e45c25 100644
--- a/features/netsocket/emac-drivers/TARGET_STM/mbed_lib.json
+++ b/features/netsocket/emac-drivers/TARGET_STM/mbed_lib.json
@@ -11,6 +11,10 @@
             "help" : "Configures actual PHY address according to pullup/down status of PHYAD pin(s)",
             "value" : 0
         },
+        "eth-phy-media-interface": {
+            "help" : "Selects Connection to PHY Chip: ETH_MEDIA_INTERFACE_RMII / ETH_MEDIA_INTERFACE_MII",
+            "value" : "ETH_MEDIA_INTERFACE_RMII"
+        },
         "eth-phy-AutoNegotiation": {
             "help" : "Selects AutoNegotiation mode : ETH_AUTONEGOTIATION_ENABLE / ETH_AUTONEGOTIATION_DISABLE",
             "value" : "ETH_AUTONEGOTIATION_ENABLE"
diff --git a/features/netsocket/emac-drivers/TARGET_STM/stm32xx_emac.cpp b/features/netsocket/emac-drivers/TARGET_STM/stm32xx_emac.cpp
index d5b5c5e90f..9c34811179 100644
--- a/features/netsocket/emac-drivers/TARGET_STM/stm32xx_emac.cpp
+++ b/features/netsocket/emac-drivers/TARGET_STM/stm32xx_emac.cpp
@@ -313,7 +313,7 @@ bool STM32_EMAC::low_level_init_successful()
     EthHandle.Init.MACAddr = &MACAddr[0];
     EthHandle.Init.RxMode = ETH_RXINTERRUPT_MODE;
     EthHandle.Init.ChecksumMode = ETH_CHECKSUM_BY_SOFTWARE;
-    EthHandle.Init.MediaInterface = ETH_MEDIA_INTERFACE_RMII;
+    EthHandle.Init.MediaInterface = MBED_CONF_STM32_EMAC_ETH_PHY_MEDIA_INTERFACE;
     tr_info("PHY Addr %u AutoNegotiation %u", EthHandle.Init.PhyAddress, EthHandle.Init.AutoNegotiation);
     tr_debug("MAC Addr %02x:%02x:%02x:%02x:%02x:%02x", MACAddr[0], MACAddr[1], MACAddr[2], MACAddr[3], MACAddr[4], MACAddr[5]);
     tr_info("ETH buffers : %u Rx %u Tx", ETH_RXBUFNB, ETH_TXBUFNB);