diff -r 06cb0d602468 Lib/test/test_unicode.py
--- a/Lib/test/test_unicode.py	Sun Jul 03 23:16:49 2011 -0700
+++ b/Lib/test/test_unicode.py	Mon Jul 04 11:32:11 2011 +0200
@@ -404,6 +404,7 @@
         self.assertEqual(u'%c' % 0x1234, u'\u1234')
         self.assertRaises(OverflowError, u"%c".__mod__, (sys.maxunicode+1,))
         self.assertRaises(ValueError, u"%.1\u1032f".__mod__, (1.0/3))
+        self.assertRaises(TypeError, "%i".__mod__, "aa")
 
         for num in range(0x00,0x80):
             char = chr(num)
diff -r 06cb0d602468 Objects/unicodeobject.c
--- a/Objects/unicodeobject.c	Sun Jul 03 23:16:49 2011 -0700
+++ b/Objects/unicodeobject.c	Mon Jul 04 11:32:11 2011 +0200
@@ -8505,8 +8505,6 @@
             case 'o':
             case 'x':
             case 'X':
-                if (c == 'i')
-                    c = 'd';
                 isnumok = 0;
                 if (PyNumber_Check(v)) {
                     PyObject *iobj=NULL;
@@ -8524,7 +8522,7 @@
                             isnumok = 1;
                             pbuf = formatbuf;
                             len = formatint(pbuf, sizeof(formatbuf)/sizeof(Py_UNICODE),
-                                            flags, prec, c, iobj);
+                                            flags, prec, (c == 'i'? 'd': c), iobj);
                             Py_DECREF(iobj);
                             if (len < 0)
                                 goto onError;
@@ -8532,7 +8530,7 @@
                         }
                         else if (PyLong_Check(iobj)) {
                             isnumok = 1;
-                            temp = formatlong(iobj, flags, prec, c);
+                            temp = formatlong(iobj, flags, prec, (c == 'i'? 'd': c));
                             Py_DECREF(iobj);
                             if (!temp)
                                 goto onError;