diff --git a/jtag/ChangeLog b/jtag/ChangeLog
index 2ea1ddbe..7584b6c1 100644
--- a/jtag/ChangeLog
+++ b/jtag/ChangeLog
@@ -1,5 +1,7 @@
 2008-12-21  Kolja Waschk <kawk>
 
+   * src/svf/svf.c: Fix 2456021 - SVF compare_tdo flaw
+
    * src/tap/cable/ft2232.c, src/tap/cable/cmd_xfer.c,
      src/tap/cable/cmd_xfer.h: limit maximum number of bytes queued 
      into one cmd buffer. Should fix problems with high clocks count for
diff --git a/jtag/src/svf/svf.c b/jtag/src/svf/svf.c
index bfb78d57..61b68d15 100644
--- a/jtag/src/svf/svf.c
+++ b/jtag/src/svf/svf.c
@@ -437,7 +437,7 @@ svf_compare_tdo(parser_priv_t *priv, char *tdo, char *mask, tap_register *reg, Y
 
   mismatch = -1;
   for (pos = 0; pos < reg->len; pos++)
-    if ((svf_hex2dec(tdo_bit[pos]) ^ reg->string[pos]) & svf_hex2dec(mask_bit[pos]))
+    if ((tdo_bit[pos] != reg->string[pos]) && (mask_bit[pos] == '1'))
       mismatch = pos;
 
   if (mismatch >= 0) {