diff --git a/boot/bootutil/src/bootutil_misc.c b/boot/bootutil/src/bootutil_misc.c
index 84e77e1..46aaa61 100644
--- a/boot/bootutil/src/bootutil_misc.c
+++ b/boot/bootutil/src/bootutil_misc.c
@@ -567,9 +567,11 @@
                          table->swap_type == BOOT_SWAP_TYPE_PERM   ? "perm"   :
                          table->swap_type == BOOT_SWAP_TYPE_REVERT ? "revert" :
                          "BUG; can't happen");
-            assert(table->swap_type == BOOT_SWAP_TYPE_TEST ||
-                   table->swap_type == BOOT_SWAP_TYPE_PERM ||
-                   table->swap_type == BOOT_SWAP_TYPE_REVERT);
+            if (table->swap_type != BOOT_SWAP_TYPE_TEST &&
+                    table->swap_type != BOOT_SWAP_TYPE_PERM &&
+                    table->swap_type != BOOT_SWAP_TYPE_REVERT) {
+                return BOOT_SWAP_TYPE_PANIC;
+            }
             return table->swap_type;
         }
     }