Index: sys/dev/bge/if_bgereg.h
===================================================================
--- sys/dev/bge/if_bgereg.h	(revision 202268)
+++ sys/dev/bge/if_bgereg.h	(working copy)
@@ -2603,6 +2603,7 @@
 #define	BGE_FLAG_JUMBO		0x00000002
 #define	BGE_FLAG_WIRESPEED	0x00000004
 #define	BGE_FLAG_EADDR		0x00000008
+#define	BGE_FLAG_MII_SERDES	0x00000010
 #define	BGE_FLAG_MSI		0x00000100
 #define	BGE_FLAG_PCIX		0x00000200
 #define	BGE_FLAG_PCIE		0x00000400
Index: sys/dev/bge/if_bge.c
===================================================================
--- sys/dev/bge/if_bge.c	(revision 202268)
+++ sys/dev/bge/if_bge.c	(working copy)
@@ -902,7 +902,8 @@
 	mii = device_get_softc(sc->bge_miibus);
 
 	BGE_CLRBIT(sc, BGE_MAC_MODE, BGE_MACMODE_PORTMODE);
-	if (IFM_SUBTYPE(mii->mii_media_active) == IFM_1000_T)
+	if (IFM_SUBTYPE(mii->mii_media_active) == IFM_1000_T ||
+	    IFM_SUBTYPE(mii->mii_media_active) == IFM_1000_SX)
 		BGE_SETBIT(sc, BGE_MAC_MODE, BGE_PORTMODE_GMII);
 	else
 		BGE_SETBIT(sc, BGE_MAC_MODE, BGE_PORTMODE_MII);
@@ -1783,13 +1784,20 @@
 	if (!(BGE_IS_5705_PLUS(sc)))
 		CSR_WRITE_4(sc, BGE_RXLS_MODE, BGE_RXLSMODE_ENABLE);
 
+	val = BGE_MACMODE_TXDMA_ENB | BGE_MACMODE_RXDMA_ENB |
+	    BGE_MACMODE_RX_STATS_CLEAR | BGE_MACMODE_TX_STATS_CLEAR |
+	    BGE_MACMODE_RX_STATS_ENB | BGE_MACMODE_TX_STATS_ENB |
+	    BGE_MACMODE_FRMHDR_DMA_ENB;
+
+	if (sc->bge_flags & BGE_FLAG_TBI)
+		val |= BGE_PORTMODE_TBI;
+	else if (sc->bge_flags & BGE_FLAG_MII_SERDES)
+		val |= BGE_PORTMODE_GMII;
+	else
+		val |= BGE_PORTMODE_MII;
+
 	/* Turn on DMA, clear stats */
-	CSR_WRITE_4(sc, BGE_MAC_MODE, BGE_MACMODE_TXDMA_ENB |
-	    BGE_MACMODE_RXDMA_ENB | BGE_MACMODE_RX_STATS_CLEAR |
-	    BGE_MACMODE_TX_STATS_CLEAR | BGE_MACMODE_RX_STATS_ENB |
-	    BGE_MACMODE_TX_STATS_ENB | BGE_MACMODE_FRMHDR_DMA_ENB |
-	    ((sc->bge_flags & BGE_FLAG_TBI) ?
-	    BGE_PORTMODE_TBI : BGE_PORTMODE_MII));
+	CSR_WRITE_4(sc, BGE_MAC_MODE, val);
 
 	/* Set misc. local control, enable interrupts on attentions */
 	CSR_WRITE_4(sc, BGE_MISC_LOCAL_CTL, BGE_MLC_INTR_ONATTN);
@@ -2851,12 +2859,14 @@
 		hwcfg = ntohl(hwcfg);
 	}
 
-	if ((hwcfg & BGE_HWCFG_MEDIA) == BGE_MEDIA_FIBER)
-		sc->bge_flags |= BGE_FLAG_TBI;
-
 	/* The SysKonnect SK-9D41 is a 1000baseSX card. */
-	if ((pci_read_config(dev, BGE_PCI_SUBSYS, 4) >> 16) == SK_SUBSYSID_9D41)
-		sc->bge_flags |= BGE_FLAG_TBI;
+	if ((pci_read_config(dev, BGE_PCI_SUBSYS, 4) >> 16) ==
+	    SK_SUBSYSID_9D41 || (hwcfg & BGE_HWCFG_MEDIA) == BGE_MEDIA_FIBER) {
+		if (BGE_IS_5714_FAMILY(sc))
+			sc->bge_flags |= BGE_FLAG_MII_SERDES;
+		else
+			sc->bge_flags |= BGE_FLAG_TBI;
+	}
 
 	if (sc->bge_flags & BGE_FLAG_TBI) {
 		ifmedia_init(&sc->bge_ifmedia, IFM_IMASK, bge_ifmedia_upd,
Index: sys/dev/mii/brgphy.c
===================================================================
--- sys/dev/mii/brgphy.c	(revision 202269)
+++ sys/dev/mii/brgphy.c	(working copy)
@@ -197,6 +197,7 @@
 	case MII_OUI_xxBROADCOM:
 		switch (bsc->mii_model) {
 			case MII_MODEL_xxBROADCOM_BCM5706:
+			case MII_MODEL_xxBROADCOM_BCM5714:
 				/*
 				 * The 5464 PHY used in the 5706 supports both copper
 				 * and fiber interfaces over GMII.  Need to check the