diff --git a/lib/buffer.js b/lib/buffer.js
index 615d192ce43014..01b9ea97f95a68 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -292,17 +292,21 @@ Buffer.from = function from(value, encodingOrOffset, length) {
       return fromArrayBuffer(value, encodingOrOffset, length);
 
     const valueOf = value.valueOf && value.valueOf();
-    if (valueOf !== null && valueOf !== undefined && valueOf !== value)
-      return Buffer.from(valueOf, encodingOrOffset, length);
+    if (valueOf != null &&
+        valueOf !== value &&
+        (typeof valueOf === 'string' || typeof valueOf === 'object')) {
+      return from(valueOf, encodingOrOffset, length);
+    }
 
     const b = fromObject(value);
     if (b)
       return b;
 
     if (typeof value[SymbolToPrimitive] === 'function') {
-      return Buffer.from(value[SymbolToPrimitive]('string'),
-                         encodingOrOffset,
-                         length);
+      const primitive = value[SymbolToPrimitive]('string');
+      if (typeof primitive === 'string') {
+        return fromString(primitive, encodingOrOffset);
+      }
     }
   }