diff --git a/internal/generator/ecdsa/template/ecdsa.test.go.tmpl b/internal/generator/ecdsa/template/ecdsa.test.go.tmpl
index e12cd48fe..1b15de76d 100644
--- a/internal/generator/ecdsa/template/ecdsa.test.go.tmpl
+++ b/internal/generator/ecdsa/template/ecdsa.test.go.tmpl
@@ -111,6 +111,7 @@ func TestNonMalleability(t *testing.T) {
 		r.Add(r, frMod)
 		buf := r.Bytes()
 		copy(bsig[sizeFr:], buf[:])
+		big.NewInt(1).FillBytes(bsig[:sizeFr])
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)
diff --git a/internal/generator/edwards/eddsa/template/eddsa.test.go.tmpl b/internal/generator/edwards/eddsa/template/eddsa.test.go.tmpl
index f95f9cea5..bdc6fdf7b 100644
--- a/internal/generator/edwards/eddsa/template/eddsa.test.go.tmpl
+++ b/internal/generator/edwards/eddsa/template/eddsa.test.go.tmpl
@@ -79,6 +79,7 @@ func TestNonMalleability(t *testing.T) {
 		o.Add(&cp.Order, o)
 		buf := o.Bytes()
 		copy(bsig[sizeFr:], buf[:])
+		big.NewInt(1).FillBytes(bsig[:sizeFr])
 
 		var sig Signature
 		_, err := sig.SetBytes(bsig)