diff --git a/drivers/net/fm/p1023.c b/drivers/net/fm/p1023.c
index b17dc40b8a8f900fe73ee7386652d1929f447afd..9765da5b2354af0e196e9f40f7b93015619c346d 100644
--- a/drivers/net/fm/p1023.c
+++ b/drivers/net/fm/p1023.c
@@ -39,6 +39,11 @@ static int is_device_disabled(enum fm_port port)
 void fman_disable_port(enum fm_port port)
 {
 	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+
+	/* don't allow disabling of DTSEC1 as its needed for MDIO */
+	if (port == FM1_DTSEC1)
+		return;
+
 	setbits_be32(&gur->devdisr, port_to_devdisr[port]);
 }
 
diff --git a/drivers/net/fm/p3060.c b/drivers/net/fm/p3060.c
index 176e1d292cfe21bca0b52854ab6ec8781752dfc1..c9748a954cca44eda07323f013f7d49a457f7d4c 100644
--- a/drivers/net/fm/p3060.c
+++ b/drivers/net/fm/p3060.c
@@ -45,6 +45,11 @@ static int is_device_disabled(enum fm_port port)
 void fman_disable_port(enum fm_port port)
 {
 	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+
+	/* don't allow disabling of DTSEC1 as its needed for MDIO */
+	if (port == FM1_DTSEC1)
+		return;
+
 	setbits_be32(&gur->devdisr2, port_to_devdisr[port]);
 }
 
diff --git a/drivers/net/fm/p4080.c b/drivers/net/fm/p4080.c
index 791caab7ecda51772c086d12e9f573e7e0dc3d39..9dc6049c360cc1bc267ccbca5f8a04fda8bc1848 100644
--- a/drivers/net/fm/p4080.c
+++ b/drivers/net/fm/p4080.c
@@ -47,6 +47,11 @@ static int is_device_disabled(enum fm_port port)
 void fman_disable_port(enum fm_port port)
 {
 	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+
+	/* don't allow disabling of DTSEC1 as its needed for MDIO */
+	if (port == FM1_DTSEC1)
+		return;
+
 	setbits_be32(&gur->devdisr2, port_to_devdisr[port]);
 }
 
diff --git a/drivers/net/fm/p5020.c b/drivers/net/fm/p5020.c
index 69c27d22371fa7b1a36c54283cde092fe30c03b6..a7a6e43fe2c038293878f1ae6b59a8e3a8f760e0 100644
--- a/drivers/net/fm/p5020.c
+++ b/drivers/net/fm/p5020.c
@@ -43,6 +43,11 @@ static int is_device_disabled(enum fm_port port)
 void fman_disable_port(enum fm_port port)
 {
 	ccsr_gur_t *gur = (void *)(CONFIG_SYS_MPC85xx_GUTS_ADDR);
+
+	/* don't allow disabling of DTSEC1 as its needed for MDIO */
+	if (port == FM1_DTSEC1)
+		return;
+
 	setbits_be32(&gur->devdisr2, port_to_devdisr[port]);
 }