diff --git a/configs/freedom-k66f/include/board.h b/configs/freedom-k66f/include/board.h
index 6ddf405152d..ec914b7aab0 100644
--- a/configs/freedom-k66f/include/board.h
+++ b/configs/freedom-k66f/include/board.h
@@ -277,6 +277,45 @@
 #define PIN_I2C0_SCL      PIN_I2C0_SCL_3
 #define PIN_I2C0_SDA      PIN_I2C0_SDA_3
 
+/*
+ * Ethernet MAC/KSZ8081 PHY
+ *  ------------------------
+ *  ------------ ----------------- --------------------------------------------
+ * KSZ8081      Board Signal(s)   K66F Pin
+ * Pin Signal                     Function                       pinmux Name
+ * --- -------- ----------------- --------------------------------------------
+ *  1  VDD_1V2  VDDPLL_1.2V       ---                            ---
+ *  2  VDDA_3V3 VDDA_ENET         ---                            ---
+ *  3  RXM      ENET1_RX-         ---                            ---
+ *  4  RXP      ENET1_RX+         ---                            ---
+ *  5  TXM      ENET1_TX-         ---                            ---
+ *  6  TXP      ENET1_TX+         ---                            ---
+ *  7  X0       RMII_XTAL0        ---                            ---
+ *  8  XI       RMII_XTAL1        ---                            ---
+ *  9  REXT     ---               ---, Apparently not connected  ---
+ * 10  MDIO     RMII0_MDIO        PTB0/RMII0_MDIO                PIN_RMII0_MDIO
+ * 11  MDC      RMII0_MDC         PTB1/RMII0_MDC                 PIN_RMII0_MDC
+ * 12  RXD1     RMII0_RXD_1       PTA12/RMII0_RXD1               PIN_RMII0_RXD1
+ * 13  RXD0     RMII0_RXD_0       PTA13/RMII0_RXD0               PIN_RMII0_RXD0
+ * 14  VDDIO    VDDIO_ENET        ---                            ---
+ * 15  CRS_DIV                    PTA14/RMII0_CRS_DV             PIN_RMII0_CRS_DV
+ * 16  REF_CLK  PTE26             PTE26(Ethernet clock)          PTE26/ENET_1588_CLKIN
+ * 17  RXER     RMII0_RXER        PTA5/RMII0_RXER                PIN_RMII0_RXER
+ * 18  INTRP    RMII0_INT_B,      J14 Pin 2, Apparently not      ---
+ *              PHY_INT_1         available unless jumpered
+ * 19  TXEN     RMII0_TXEN        PTA15/RMII0_TXEN               PIN_RMII0_TXEN
+ * 20  TXD0     RMII0_TXD_0       PTA16/RMII0_TXD0               PIN_RMII0_TXD0
+ * 21  TXD1     RMII0_TXD_1       PTA17/RMII0_TXD1               PIN_RMII0_TXD1
+ * 22  GND1     ---               ---                            ---
+ * 24  nRST     PHY_RST_B         ---                            ---
+ * 25  GND2     ---               ---                            ---
+ * --- -------- ----------------- --------------------------------------------
+ *
+ */
+
+#define PIN_RMII0_MDIO  PIN_RMII0_MDIO_1
+#define PIN_RMII0_MDC   PIN_RMII0_MDC_1
+
 /************************************************************************************
  * Public Data
  ************************************************************************************/