diff --git a/arch/sim/src/up_appinit.c b/arch/sim/src/up_appinit.c
index 606186fe88f..fbbc2f8a95b 100644
--- a/arch/sim/src/up_appinit.c
+++ b/arch/sim/src/up_appinit.c
@@ -38,7 +38,11 @@
  ***************************************************************************/
 
 #include <nuttx/config.h>
+
+#include <debug.h>
+
 #include <nuttx/board.h>
+#include <nuttx/net/loopback.h>
 
 /***************************************************************************
  * Public Functions
@@ -57,6 +61,19 @@
 #ifdef CONFIG_LIB_BOARDCTL
 int board_app_initialize(void)
 {
+#ifdef CONFIG_NETDEV_LOOPBACK
+  int ret;
+
+  /* Initialize the local loopback device */
+
+  ret = localhost_initialize();
+  if (ret < 0)
+    {
+      ndbg("ERROR: localhost_initialize() failed: %d\n", ret);
+    }
+
+#endif /* CONFIG_NETDEV_LOOPBACK */
+
   return 0;
 }
 #endif /* CONFIG_LIB_BOARDCTL */
diff --git a/arch/sim/src/up_internal.h b/arch/sim/src/up_internal.h
index 257efa8d5a7..11b6b3dacc5 100644
--- a/arch/sim/src/up_internal.h
+++ b/arch/sim/src/up_internal.h
@@ -280,7 +280,7 @@ int sim_ajoy_initialize(void);
 
 /* up_tapdev.c ************************************************************/
 
-#if defined(CONFIG_NET) && !defined(__CYGWIN__)
+#if defined(CONFIG_NET_ETHERNET) && !defined(__CYGWIN__)
 void tapdev_init(void);
 unsigned int tapdev_read(unsigned char *buf, unsigned int buflen);
 void tapdev_send(unsigned char *buf, unsigned int buflen);
@@ -292,7 +292,7 @@ void tapdev_send(unsigned char *buf, unsigned int buflen);
 
 /* up_wpcap.c *************************************************************/
 
-#if defined(CONFIG_NET) && defined(__CYGWIN__)
+#if defined(CONFIG_NET_ETHERNET) && defined(__CYGWIN__)
 void wpcap_init(void);
 unsigned int wpcap_read(unsigned char *buf, unsigned int buflen);
 void wpcap_send(unsigned char *buf, unsigned int buflen);
@@ -304,7 +304,7 @@ void wpcap_send(unsigned char *buf, unsigned int buflen);
 
 /* up_netdriver.c *********************************************************/
 
-#ifdef CONFIG_NET
+#ifdef CONFIG_NET_ETHERNET
 int netdriver_init(void);
 int netdriver_setmacaddr(unsigned char *macaddr);
 void netdriver_loop(void);
diff --git a/arch/sim/src/up_netdriver.c b/arch/sim/src/up_netdriver.c
index a710a38319f..43368f3fe61 100644
--- a/arch/sim/src/up_netdriver.c
+++ b/arch/sim/src/up_netdriver.c
@@ -44,7 +44,7 @@
 
 #include <nuttx/config.h>
 
-#ifdef CONFIG_NET
+#ifdef CONFIG_NET_ETHERNET
 
 #include <stdint.h>
 #include <stdbool.h>
@@ -325,5 +325,5 @@ int netdriver_setmacaddr(unsigned char *macaddr)
   return 0;
 }
 
-#endif /* CONFIG_NET */
+#endif /* CONFIG_NET_ETHERNET */