diff --git a/lib/libfdt/libfdt.swig b/lib/libfdt/libfdt.swig
index 26d42fc..ce516fd 100644
--- a/lib/libfdt/libfdt.swig
+++ b/lib/libfdt/libfdt.swig
@@ -95,3 +95,15 @@
 const char *fdt_string(const void *fdt, int stroffset);
 int fdt_first_subnode(const void *fdt, int offset);
 int fdt_next_subnode(const void *fdt, int offset);
+
+%typemap(in) (void *) {
+  if (!PyByteArray_Check($input)) {
+    SWIG_exception_fail(SWIG_TypeError, "in method '" "$symname" "', argument "
+                       "$argnum"" of type '" "$type""'");
+  }
+  $1 = PyByteArray_AsString($input);
+}
+
+int fdt_delprop(void *fdt, int nodeoffset, const char *name);
+
+const char *fdt_strerror(int errval);