diff --git a/consts/bit.go b/consts/bit.go
index 6500464..729bdaa 100644
--- a/consts/bit.go
+++ b/consts/bit.go
@@ -28,9 +28,9 @@ func SetBitOfBytes(bs []byte, bitIndex int, v bool) []byte {
 	}
 	by := bs[bi]
 	if v {
-		by |= (1 << (7 - i))
+		by |= (1 << i)
 	} else {
-		by &= ((1 << (7 - i)) ^ byte(0xff))
+		by &= ((1 << i) ^ byte(0xff))
 	}
 	bs[bi] = by
 	return bs