diff --git a/ChangeLog b/ChangeLog
index b541d1ab5..726951d4a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2008-06-30  Matthias Clasen  <mclasen@redhat.com>
+
+	Backport from trunk:
+
+	Bug 502511 – g_assert_cmphex prints invalid message
+
+	* glib/gtestutils.c (g_assertion_message_cmpnum): Actually print
+	hex numbers in hex.
+	Pointed out by Tor Lillqvist
+
 2008-06-30  Matthias Clasen  <mclasen@redhat.com>
 
 	Backport from trunk:
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 13f670dd0..b39b94014 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -1245,7 +1245,7 @@ g_assertion_message_cmpnum (const char     *domain,
   switch (numtype)
     {
     case 'i':   s = g_strdup_printf ("assertion failed (%s): (%.0Lf %s %.0Lf)", expr, arg1, cmp, arg2); break;
-    case 'x':   s = g_strdup_printf ("assertion failed (%s): (0x%08" G_GUINT64_FORMAT " %s 0x%08" G_GUINT64_FORMAT ")", expr, (guint64) arg1, cmp, (guint64) arg2); break;
+    case 'x':   s = g_strdup_printf ("assertion failed (%s): (0x%08" G_GINT64_MODIFIER "x %s 0x%08" G_GINT64_MODIFIER "x)", expr, (guint64) arg1, cmp, (guint64) arg2); break;
     case 'f':   s = g_strdup_printf ("assertion failed (%s): (%.9Lg %s %.9Lg)", expr, arg1, cmp, arg2); break;
       /* ideally use: floats=%.7g double=%.17g */
     }