diff --git a/core/types/tx_blob.go b/core/types/tx_blob.go
index c6c31d3488..b40bef8b40 100644
--- a/core/types/tx_blob.go
+++ b/core/types/tx_blob.go
@@ -192,7 +192,7 @@ func (tx *BlobTx) withoutSidecar() *BlobTx {
 
 func (tx *BlobTx) withSidecar(sidecar *BlobTxSidecar) *BlobTx {
 	cpy := *tx
-	tx.Sidecar = sidecar
+	cpy.Sidecar = sidecar
 	return &cpy
 }