diff --git a/display/ng.c b/display/ng.c
index 1233bb73..7e2c82b5 100644
--- a/display/ng.c
+++ b/display/ng.c
@@ -25,7 +25,6 @@
  */
 
 #include <string.h>
-#include <assert.h>
 #include "display.h"                    /* XY plot interface */
 #include "ng.h"
 
@@ -123,7 +122,9 @@ int
 ng_init(void *dev, int debug)
 {
   /* Don't change this number. */
-  assert (DISPLAYS == 8);
+#if (DISPLAYS != 8) 
+#error "DISPLAYS is not 8"
+#endif
 
   ng_dptr = dev;
   ng_dbit = debug;
diff --git a/sim_defs.h b/sim_defs.h
index 5d78105f..e390be26 100644
--- a/sim_defs.h
+++ b/sim_defs.h
@@ -1093,6 +1093,14 @@ struct MEMFILE {
                                 snprintf(buf, sizeof (buf), "%s failed", #_Expression); \
                                 SIM_SCP_ABORT (buf);                                    \
                                 }
+#if defined(assert)
+#error "Don't use assert().  It is advised to use ASSURE(expression) instead"
+#else
+#define assert(_Expression) do {                                                                                             \
+                                fprintf (stderr, "Don't use assert().  It is advised to use ASSURE(expression) instead.\n"); \
+                                abort();                                                                                     \
+                                } while (1)
+#endif
 
 #if defined(SIM_ASYNCH_IO)
 #define AIO_CHECK_EVENT sim_aio_check_event()
diff --git a/slirp/tftp.c b/slirp/tftp.c
index 2d7d5a3d..c6c13709 100644
--- a/slirp/tftp.c
+++ b/slirp/tftp.c
@@ -387,7 +387,10 @@ static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
   }
 
   if (nb_options > 0) {
-      assert(nb_options <= ARRAY_SIZE(option_name));
+      if (nb_options > ARRAY_SIZE(option_name)) {
+          fprintf (stderr, "option_name array bounds: %d\n", nb_options);
+          abort ();
+      }
       tftp_send_oack(spt, option_name, option_value, nb_options, tp);
       return;
   }
diff --git a/slirp_glue/qemu/osdep.h b/slirp_glue/qemu/osdep.h
index c3d33394..81173e71 100644
--- a/slirp_glue/qemu/osdep.h
+++ b/slirp_glue/qemu/osdep.h
@@ -57,7 +57,6 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/time.h>
-#include <assert.h>
 #include <signal.h>
 
 #ifdef __OpenBSD__