diff --git a/src/stringify.js b/src/stringify.js
index 3d15e61a..3e66728d 100644
--- a/src/stringify.js
+++ b/src/stringify.js
@@ -34,7 +34,7 @@ export function unsafeStringify(arr, offset = 0) {
     byteToHex[arr[offset + 13]] +
     byteToHex[arr[offset + 14]] +
     byteToHex[arr[offset + 15]]
-  );
+  ).toLowerCase();
 }
 
 function stringify(arr, offset = 0) {