diff --git a/build/files.js b/build/files.js
index 81f075c70b..ec2399e9b5 100644
--- a/build/files.js
+++ b/build/files.js
@@ -180,11 +180,12 @@ const headRegexp = /(^module.exports = \w+;?)/m
       /(?:var|const) Buffer = require\('buffer'\)\.Buffer;/
     , `/*<replacement>*/
   const Buffer = require('safe-buffer').Buffer
+  const OurUint8Array = global.Uint8Array || function () {}
 function _uint8ArrayToBuffer(chunk) {
    return Buffer.from(chunk);
 }
 function _isUint8Array(obj) {
-  return Object.prototype.toString.call(obj) === '[object Uint8Array]' || Buffer.isBuffer(obj);
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
 }
 /*</replacement>*/
   `
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index 2279be9f93..ea9f8b8531 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -54,11 +54,12 @@ var Stream = require('./internal/streams/stream');
 // properly optimized away early in Ignition+TurboFan.
 /*<replacement>*/
 var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = global.Uint8Array || function () {};
 function _uint8ArrayToBuffer(chunk) {
   return Buffer.from(chunk);
 }
 function _isUint8Array(obj) {
-  return Object.prototype.toString.call(obj) === '[object Uint8Array]' || Buffer.isBuffer(obj);
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
 }
 /*</replacement>*/
 
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index ad38c6aa8d..72630a6585 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -80,11 +80,12 @@ var Stream = require('./internal/streams/stream');
 
 /*<replacement>*/
 var Buffer = require('safe-buffer').Buffer;
+var OurUint8Array = global.Uint8Array || function () {};
 function _uint8ArrayToBuffer(chunk) {
   return Buffer.from(chunk);
 }
 function _isUint8Array(obj) {
-  return Object.prototype.toString.call(obj) === '[object Uint8Array]' || Buffer.isBuffer(obj);
+  return Buffer.isBuffer(obj) || obj instanceof OurUint8Array;
 }
 /*</replacement>*/
 
@@ -408,26 +409,15 @@ function doWrite(stream, state, writev, len, chunk, encoding, cb) {
 
 function onwriteError(stream, state, sync, er, cb) {
   --state.pendingcb;
+  if (sync) processNextTick(afterError, stream, state, cb, er);else afterError(stream, state, cb, er);
 
-  if (sync) {
-    // defer the callback if we are being called synchronously
-    // to avoid piling up things on the stack
-    processNextTick(cb, er);
-    // this can emit finish, and it will always happen
-    // after error
-    processNextTick(finishMaybe, stream, state);
-    stream._writableState.errorEmitted = true;
-    stream.emit('error', er);
-  } else {
-    // the caller expect this to happen before if
-    // it is async
-    cb(er);
-    stream._writableState.errorEmitted = true;
-    stream.emit('error', er);
-    // this can emit finish, but finish must
-    // always follow error
-    finishMaybe(stream, state);
-  }
+  stream._writableState.errorEmitted = true;
+  stream.emit('error', er);
+}
+
+function afterError(stream, state, cb, err) {
+  cb(err);
+  finishMaybe(stream, state);
 }
 
 function onwriteStateUpdate(state) {
@@ -660,4 +650,4 @@ Writable.prototype._undestroy = destroyImpl.undestroy;
 Writable.prototype._destroy = function (err, cb) {
   this.end();
   cb(err);
-};
+};
\ No newline at end of file