--- mysql-5.1.30/sql/sql_update.cc	2008-11-14 08:37:23.000000000 -0800
+++ mysql-5.1.30.patched/sql/sql_update.cc	2008-12-18 10:46:30.000000000 -0800
@@ -526,9 +526,9 @@
   init_read_record(&info, thd, table, select, 0, 1, FALSE);
 
   updated= found= 0;
-  /* Generate an error when trying to set a NOT NULL field to NULL. */
-  thd->count_cuted_fields= ignore ? CHECK_FIELD_WARN
-                                  : CHECK_FIELD_ERROR_FOR_NULL;
+  /* Generate an warning when trying to set a NOT NULL field to NULL. */
+  thd->count_cuted_fields = CHECK_FIELD_WARN;
+
   thd->cuted_fields=0L;
   thd_proc_info(thd, "Updating");