diff --git a/sim_ether.c b/sim_ether.c
index 916769c1..cf5cf438 100644
--- a/sim_ether.c
+++ b/sim_ether.c
@@ -1902,9 +1902,9 @@ sim_debug(dev->dbit, dev->dptr, "Writer Thread Starting\n");
 pthread_mutex_lock (&dev->writer_lock);
 while (dev->handle) {
   pthread_cond_wait (&dev->writer_cond, &dev->writer_lock);
-  if (dev->handle == NULL)      /* Shutting down? */
-      break;
   while (NULL != (request = dev->write_requests)) {
+    if (dev->handle == NULL)      /* Shutting down? */
+      break;
     /* Pull buffer off request list */
     dev->write_requests = request->next;
     pthread_mutex_unlock (&dev->writer_lock);
diff --git a/slirp_glue/sim_slirp.c b/slirp_glue/sim_slirp.c
index f44d1b95..b63af46f 100644
--- a/slirp_glue/sim_slirp.c
+++ b/slirp_glue/sim_slirp.c
@@ -456,6 +456,10 @@ int sim_slirp_send (SLIRP *slirp, const char *msg, size_t len, int flags)
 struct slirp_write_request *request;
 int wake_needed = 0;
 
+if (!slirp) {
+    errno = EBADF;
+    return 0;
+    }
 /* Get a buffer */
 pthread_mutex_lock (&slirp->write_buffer_lock);
 if (NULL != (request = slirp->write_buffers))