diff --git a/board/freescale/t4rdb/eth.c b/board/freescale/t4rdb/eth.c
index e563a61..ae2451e 100644
--- a/board/freescale/t4rdb/eth.c
+++ b/board/freescale/t4rdb/eth.c
@@ -77,6 +77,9 @@
 		puts("Invalid SerDes1 protocol for T4240RDB\n");
 	}
 
+	fm_disable_port(FM1_DTSEC5);
+	fm_disable_port(FM1_DTSEC6);
+
 	for (i = FM1_DTSEC1; i < FM1_DTSEC1 + CONFIG_SYS_NUM_FM1_DTSEC; i++) {
 		interface = fm_info_get_enet_if(i);
 		switch (interface) {
@@ -115,6 +118,8 @@
 		puts("Invalid SerDes2 protocol for T4240RDB\n");
 	}
 
+	fm_disable_port(FM2_DTSEC5);
+	fm_disable_port(FM2_DTSEC6);
 	for (i = FM2_DTSEC1; i < FM2_DTSEC1 + CONFIG_SYS_NUM_FM2_DTSEC; i++) {
 		interface = fm_info_get_enet_if(i);
 		switch (interface) {