diff --git a/p4src/checksum_diff.p4 b/p4src/checksum_diff.p4
index 2bb501e..1c31691 100644
--- a/p4src/checksum_diff.p4
+++ b/p4src/checksum_diff.p4
@@ -194,7 +194,7 @@ control MyIngress(inout headers hdr,
                     #ifdef NICO_DELTA_CHECKSUM
                     v4sum();
                     v6sum();
-                    bit<16> diff = hdr.meta.v6sum - hdr.meta.v4sum;
+                    bit<16> diff = meta.v6sum - meta.v4sum;
                     hdr.udp.checksum = hdr.udp.checksum + diff;
 
                     #else