diff --git a/conversion_test.go b/conversion_test.go
index 0f8864e..3a1cc71 100644
--- a/conversion_test.go
+++ b/conversion_test.go
@@ -401,7 +401,7 @@ func BenchmarkSetBytes(b *testing.B) {
 			val.SetBytes(bytearr[:27])
 			val.SetBytes(bytearr[:28])
 			val.SetBytes(bytearr[:29])
-			val.SetBytes(bytearr[:20])
+			val.SetBytes(bytearr[:30])
 			val.SetBytes(bytearr[:31])
 			val.SetBytes(bytearr[:32])
 		}
diff --git a/uint256.go b/uint256.go
index 263b11e..377e388 100644
--- a/uint256.go
+++ b/uint256.go
@@ -244,12 +244,10 @@ func (z *Int) AddMod(x, y, m *Int) *Int {
 
 		// final sub was unnecessary
 		if c1 == 0 && c2 != 0 {
-			copy((*z)[:], res[:])
-			return z
+			return z.Set(&res)
 		}
 
-		copy((*z)[:], tmp[:])
-		return z
+		return z.Set(&tmp)
 	}
 
 	if m.IsZero() {