diff --git a/boards/sim/sim/sim/configs/rpproxy/defconfig b/boards/sim/sim/sim/configs/rpproxy/defconfig
index 0a9a9282b26..c748c2fda73 100644
--- a/boards/sim/sim/sim/configs/rpproxy/defconfig
+++ b/boards/sim/sim/sim/configs/rpproxy/defconfig
@@ -5,6 +5,7 @@
 # You can then do "make savedefconfig" to generate a new defconfig file that includes your
 # modifications.
 #
+# CONFIG_SIM_NETDEV is not set
 CONFIG_ARCH="sim"
 CONFIG_ARCH_BOARD="sim"
 CONFIG_ARCH_BOARD_SIM=y
@@ -20,6 +21,7 @@ CONFIG_FS_HOSTFS=y
 CONFIG_FS_HOSTFS_RPMSG=y
 CONFIG_FS_PROCFS=y
 CONFIG_FS_ROMFS=y
+CONFIG_FS_UNIONFS=y
 CONFIG_HAVE_CXX=y
 CONFIG_IDLETHREAD_STACKSIZE=4096
 CONFIG_LIBC_FLOATINGPOINT=y
@@ -29,6 +31,7 @@ CONFIG_NETDB_DNSCLIENT=y
 CONFIG_NETDB_DNSCLIENT_MAXRESPONSE=176
 CONFIG_NETDB_DNSCLIENT_RECV_TIMEOUT=3
 CONFIG_NETDB_DNSSERVER_IPv4ADDR=0x771d1d1d
+CONFIG_NETDEV_IFINDEX=y
 CONFIG_NETUTILS_USRSOCK_RPMSG=y
 CONFIG_NET_ICMP_NO_STACK=y
 CONFIG_NET_RPMSG=y
@@ -59,9 +62,9 @@ CONFIG_RTC_RPMSG=y
 CONFIG_SCHED_CHILD_STATUS=y
 CONFIG_SCHED_HAVE_PARENT=y
 CONFIG_SCHED_HPWORK=y
+CONFIG_SCHED_LPWORK=y
 CONFIG_SCHED_WAITPID=y
 CONFIG_SERIAL_TERMIOS=y
-CONFIG_SIG_DEFAULT=y
 CONFIG_SIM_M32=y
 CONFIG_STACK_COLORATION=y
 CONFIG_SYSLOG_PREFIX=y
diff --git a/boards/sim/sim/sim/src/etc/init.d/rcS b/boards/sim/sim/sim/src/etc/init.d/rcS
index 5cffe839551..d6ec6a58f61 100644
--- a/boards/sim/sim/sim/src/etc/init.d/rcS
+++ b/boards/sim/sim/sim/src/etc/init.d/rcS
@@ -46,6 +46,14 @@ mount -t vfat CONCAT(/dev/ram, CONFIG_NSH_FATDEVNO) CONFIG_NSH_FATMOUNTPT
 #ifdef CONFIG_FS_HOSTFS_RPMSG
 mount -t hostfs -o fs=/system /system
 mount -t hostfs -o fs=/data /data
+
+  #if defined (CONFIG_NSH_PROC_MOUNTPOINT) && defined (CONFIG_FS_UNIONFS)
+    umount CONFIG_NSH_PROC_MOUNTPOINT
+    mount -t procfs /proc1
+    mount -t hostfs -o fs=/proc/net /net2
+    mount -t unionfs -o fspath1=/proc1,fspath2=/net2,prefix2=net CONFIG_NSH_PROC_MOUNTPOINT
+  #endif
+
 #else
 mount -t hostfs -o fs=../apps /system
 mount -t hostfs -o fs=. /data
@@ -97,3 +105,9 @@ bttester
 sensor &
 
 #endif /* CONFIG_SENSOR_MANAGER */
+
+#if defined (CONFIG_NET_USRSOCK)
+  usrsock server &
+#elif defined (CONFIG_NETUTILS_USRSOCK_RPMSG)
+  usrsock &
+#endif