diff --git a/lib/buffer.js b/lib/buffer.js
index 01a8f303e1..b138552ef9 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -185,7 +185,7 @@ function fromString(string, encoding) {
 function fromArrayLike(obj) {
   const length = obj.length;
   const b = allocate(length);
-  for (let i = 0; i < length; i++)
+  for (var i = 0; i < length; i++)
     b[i] = obj[i] & 255;
   return b;
 }
@@ -276,6 +276,7 @@ Buffer.isEncoding = function(encoding) {
 
 
 Buffer.concat = function(list, length) {
+  var i;
   if (!Array.isArray(list))
     throw new TypeError('"list" argument must be an Array of Buffers');
 
@@ -284,7 +285,7 @@ Buffer.concat = function(list, length) {
 
   if (length === undefined) {
     length = 0;
-    for (let i = 0; i < list.length; i++)
+    for (i = 0; i < list.length; i++)
       length += list[i].length;
   } else {
     length = length >>> 0;
@@ -292,7 +293,7 @@ Buffer.concat = function(list, length) {
 
   var buffer = Buffer.allocUnsafe(length);
   var pos = 0;
-  for (let i = 0; i < list.length; i++) {
+  for (i = 0; i < list.length; i++) {
     var buf = list[i];
     if (!Buffer.isBuffer(buf))
       throw new TypeError('"list" argument must be an Array of Buffers');