diff --git a/arch/sim/src/sim/posix/sim_hostmemory.c b/arch/sim/src/sim/posix/sim_hostmemory.c
index 4677b70681..f65d820c64 100644
--- a/arch/sim/src/sim/posix/sim_hostmemory.c
+++ b/arch/sim/src/sim/posix/sim_hostmemory.c
@@ -92,32 +92,20 @@ void host_freeheap(void *mem)
   host_uninterruptible(munmap, mem, 0);
 }
 
-void *host_allocshmem(const char *name, size_t size, int master)
+void *host_allocshmem(const char *name, size_t size)
 {
   void *mem;
   int oflag;
   int ret;
   int fd;
 
-  oflag = O_RDWR;
-  if (master)
-    {
-      oflag |= O_CREAT | O_TRUNC;
-    }
-
+  oflag = O_RDWR | O_CREAT;
   fd = host_uninterruptible(shm_open, name, oflag, S_IRUSR | S_IWUSR);
   if (fd < 0)
     {
       return NULL;
     }
 
-  if (!master)
-    {
-      /* Avoid the second slave instance open successfully */
-
-      host_unlinkshmem(name);
-    }
-
   ret = host_uninterruptible(ftruncate, fd, size);
   if (ret < 0)
     {
diff --git a/arch/sim/src/sim/sim_internal.h b/arch/sim/src/sim/sim_internal.h
index a78260eb08..bad8bd8a8c 100644
--- a/arch/sim/src/sim/sim_internal.h
+++ b/arch/sim/src/sim/sim_internal.h
@@ -224,7 +224,7 @@ int   host_waitpid(pid_t pid);
 
 void *host_allocheap(size_t size, bool exec);
 void  host_freeheap(void *mem);
-void *host_allocshmem(const char *name, size_t size, int master);
+void *host_allocshmem(const char *name, size_t size);
 void  host_freeshmem(void *mem);
 
 size_t host_mallocsize(void *mem);
diff --git a/arch/sim/src/sim/sim_rptun.c b/arch/sim/src/sim/sim_rptun.c
index 2a1e21a3dd..fd9cb1874f 100644
--- a/arch/sim/src/sim/sim_rptun.c
+++ b/arch/sim/src/sim/sim_rptun.c
@@ -40,6 +40,12 @@
 #define SIM_RPTUN_SHIFT     16
 #define SIM_RPTUN_WORK_DELAY 1
 
+/* Status byte for master/slave to report progress */
+
+#define SIM_RPTUN_STATUS_BOOT        0x01
+#define SIM_RPTUN_STATUS_OK          0x02
+#define SIM_RPTUN_STATUS_NEED_RESET  0x04
+
 /****************************************************************************
  * Private Types
  ****************************************************************************/
@@ -51,6 +57,8 @@ struct sim_rptun_shmem_s
   volatile unsigned int     seqm;
   volatile unsigned int     cmds;
   volatile unsigned int     cmdm;
+  volatile unsigned int     boots;
+  volatile unsigned int     bootm;
   struct rptun_rsc_s        rsc;
   char                      buf[0x10000];
 };
@@ -91,24 +99,14 @@ sim_rptun_get_resource(struct rptun_dev_s *dev)
   struct sim_rptun_dev_s *priv = container_of(dev,
                                  struct sim_rptun_dev_s, rptun);
 
-  if (priv->shmem)
-    {
-      return &priv->shmem->rsc;
-    }
-
-  while (priv->shmem == NULL)
-    {
-      priv->shmem = host_allocshmem(priv->shmemname,
-                                    sizeof(*priv->shmem),
-                                    priv->master);
-      usleep(1000);
-
-      /* Master isn't ready, sleep and try again */
-    }
+  priv->shmem = host_allocshmem(priv->shmemname,
+                                sizeof(*priv->shmem));
 
   if (priv->master)
     {
       struct rptun_rsc_s *rsc = &priv->shmem->rsc;
+      memset(priv->shmem->buf, 0, sizeof(priv->shmem->buf));
+      memset(rsc, 0, sizeof(struct rptun_rsc_s));
 
       rsc->rsc_tbl_hdr.ver          = 1;
       rsc->rsc_tbl_hdr.num          = 1;
@@ -121,9 +119,11 @@ sim_rptun_get_resource(struct rptun_dev_s *dev)
                                     | 1 << VIRTIO_RPMSG_F_BUFSZ;
       rsc->rpmsg_vdev.config_len    = sizeof(struct fw_rsc_config);
       rsc->rpmsg_vdev.num_of_vrings = 2;
+      rsc->rpmsg_vring0.da          = 0;
       rsc->rpmsg_vring0.align       = 8;
       rsc->rpmsg_vring0.num         = 8;
       rsc->rpmsg_vring0.notifyid    = RSC_NOTIFY_ID_ANY;
+      rsc->rpmsg_vring1.da          = 0;
       rsc->rpmsg_vring1.align       = 8;
       rsc->rpmsg_vring1.num         = 8;
       rsc->rpmsg_vring1.notifyid    = RSC_NOTIFY_ID_ANY;
@@ -131,16 +131,36 @@ sim_rptun_get_resource(struct rptun_dev_s *dev)
       rsc->config.h2r_buf_size      = 0x800;
 
       priv->shmem->base             = (uintptr_t)priv->shmem;
+
+      /* The master notifies its slave when it starts again */
+
+      if (priv->shmem->boots & SIM_RPTUN_STATUS_OK)
+        {
+          priv->shmem->boots = SIM_RPTUN_STATUS_NEED_RESET;
+        }
+
+      priv->shmem->bootm = SIM_RPTUN_STATUS_BOOT;
     }
   else
     {
+      /* The slave notifies its master when it starts again */
+
+      if (priv->shmem->boots & SIM_RPTUN_STATUS_OK)
+        {
+          priv->shmem->bootm = SIM_RPTUN_STATUS_NEED_RESET;
+        }
+
+      priv->shmem->boots = SIM_RPTUN_STATUS_BOOT;
+
       /* Wait untils master is ready */
 
-      while (priv->shmem->base == 0)
+      while (!(priv->shmem->bootm & SIM_RPTUN_STATUS_OK))
         {
           usleep(1000);
         }
 
+      priv->shmem->boots = SIM_RPTUN_STATUS_OK;
+
       priv->addrenv[0].va          = (uintptr_t)priv->shmem;
       priv->addrenv[0].pa          = priv->shmem->base;
       priv->addrenv[0].size        = sizeof(*priv->shmem);
@@ -180,6 +200,14 @@ static int sim_rptun_start(struct rptun_dev_s *dev)
       priv->pid = pid;
     }
 
+  /* Wait until slave has started */
+
+  while (!(priv->shmem->boots & SIM_RPTUN_STATUS_BOOT))
+    {
+      usleep(1000);
+    }
+
+  priv->shmem->bootm = SIM_RPTUN_STATUS_OK;
   return 0;
 }
 
@@ -188,13 +216,21 @@ static int sim_rptun_stop(struct rptun_dev_s *dev)
   struct sim_rptun_dev_s *priv = container_of(dev,
                               struct sim_rptun_dev_s, rptun);
 
-  if ((priv->master & SIM_RPTUN_BOOT) && (priv->pid > 0))
+  /* Don't send SIM_RPTUN_STOP when slave recovery */
+
+  if (priv->shmem->boots & SIM_RPTUN_STATUS_OK)
     {
       priv->shmem->cmdm = SIM_RPTUN_STOP << SIM_RPTUN_SHIFT;
+    }
+
+  if ((priv->master & SIM_RPTUN_BOOT) && priv->pid > 0)
+    {
       host_waitpid(priv->pid);
     }
 
-  if (priv->shmem)
+  /* Master cleans shmem when both sides are about to exit */
+
+  if (priv->shmem && (priv->shmem->boots & SIM_RPTUN_STATUS_OK))
     {
       host_freeshmem(priv->shmem);
       priv->shmem = NULL;
@@ -267,6 +303,22 @@ static void sim_rptun_check_cmd(struct sim_rptun_dev_s *priv)
     }
 }
 
+static void sim_rptun_check_reset(struct sim_rptun_dev_s *priv)
+{
+  if (priv->master &&
+      (priv->shmem->bootm & SIM_RPTUN_STATUS_NEED_RESET))
+    {
+      priv->shmem->bootm = 0;
+      rptun_boot(priv->cpuname);
+    }
+  else if (!priv->master &&
+           (priv->shmem->boots & SIM_RPTUN_STATUS_NEED_RESET))
+    {
+      priv->shmem->boots = 0;
+      rptun_boot(priv->cpuname);
+    }
+}
+
 static void sim_rptun_work(void *arg)
 {
   struct sim_rptun_dev_s *dev = arg;
@@ -277,6 +329,10 @@ static void sim_rptun_work(void *arg)
 
       sim_rptun_check_cmd(dev);
 
+      /* Check if master/slave need to reset */
+
+      sim_rptun_check_reset(dev);
+
       if (dev->master && dev->seq != dev->shmem->seqs)
         {
           dev->seq = dev->shmem->seqs;
diff --git a/arch/sim/src/sim/sim_uart.c b/arch/sim/src/sim/sim_uart.c
index f5e51f8c27..deced81576 100644
--- a/arch/sim/src/sim/sim_uart.c
+++ b/arch/sim/src/sim/sim_uart.c
@@ -675,7 +675,7 @@ static int sim_uartram_register(const char *devname, bool slave)
   struct uart_rambuf_s *shmem;
 
   strlcpy(name, strrchr(devname, '/') + 1, NAME_MAX);
-  shmem = host_allocshmem(name, sizeof(struct uart_rambuf_s) * 2, !slave);
+  shmem = host_allocshmem(name, sizeof(struct uart_rambuf_s) * 2);
   DEBUGASSERT(shmem);
 
   memset(shmem, 0, sizeof(struct uart_rambuf_s) * 2);
diff --git a/arch/sim/src/sim/win/sim_hostmemory.c b/arch/sim/src/sim/win/sim_hostmemory.c
index 98844efdab..e0359cb20f 100644
--- a/arch/sim/src/sim/win/sim_hostmemory.c
+++ b/arch/sim/src/sim/win/sim_hostmemory.c
@@ -56,7 +56,7 @@ void host_freeheap(void *mem)
   _aligned_free(mem);
 }
 
-void *host_allocshmem(const char *name, size_t size, int master)
+void *host_allocshmem(const char *name, size_t size)
 {
   HANDLE handle;
   void *mem;