diff --git a/blockchain/indexers/cfindex.go b/blockchain/indexers/cfindex.go
index d9beb637..bf533a3a 100644
--- a/blockchain/indexers/cfindex.go
+++ b/blockchain/indexers/cfindex.go
@@ -175,7 +175,7 @@ func makeBasicFilterForBlock(block *btcutil.Block) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	return f.Bytes(), nil
+	return f.NBytes(), nil
 }
 
 // makeExtendedFilterForBlock builds a block's extended filter, which consists
@@ -199,7 +199,7 @@ func makeExtendedFilterForBlock(block *btcutil.Block) ([]byte, error) {
 	if err != nil {
 		return nil, err
 	}
-	return f.Bytes(), nil
+	return f.NBytes(), nil
 }
 
 // makeHeaderForFilter implements the chaining logic between filters, where