diff --git a/externs/air/sys/FileSystem.hx b/externs/air/sys/FileSystem.hx
index e278a1d385..6aa4a1de12 100644
--- a/externs/air/sys/FileSystem.hx
+++ b/externs/air/sys/FileSystem.hx
@@ -1,44 +1,64 @@
 package sys;
 
+import flash.filesystem.File in FlashFile;
+
 @:dce
 @:coreApi
 class FileSystem
 {
 	public static function exists(path:String):Bool
 	{
-		return false;
+		return new FlashFile(path).exists;
 	}
 
-	public static function rename(path:String, newPath:String):Void {}
+	public static function rename(path:String, newPath:String):Void
+	{
+		new FlashFile(path).moveTo(new FlashFile(newPath));
+	}
 
 	public static function stat(path:String):sys.FileStat
 	{
+		openfl.Lib.notImplemented();
 		return null;
 	}
 
 	public static function fullPath(relPath:String):String
 	{
-		return null;
+		var flashFile = new FlashFile(relPath);
+		flashFile.canonicalize();
+		return flashFile.nativePath;
 	}
 
 	public static function absolutePath(relPath:String):String
 	{
-		return null;
+		return new FlashFile(relPath).nativePath;
 	}
 
 	public static function isDirectory(path:String):Bool
 	{
-		return false;
+		return new FlashFile(path).isDirectory;
 	}
 
-	public static function createDirectory(path:String):Void {}
+	public static function createDirectory(path:String):Void
+	{
+		new FlashFile(path).createDirectory();
+	}
 
-	public static function deleteFile(path:String):Void {}
+	public static function deleteFile(path:String):Void
+	{
+		new FlashFile(path).deleteFile();
+	}
 
-	public static function deleteDirectory(path:String):Void {}
+	public static function deleteDirectory(path:String):Void
+	{
+		new FlashFile(path).deleteDirectory(false);
+	}
 
 	public static function readDirectory(path:String):Array<String>
 	{
-		return null;
+		return new FlashFile(path).getDirectoryListing().map(function(f:FlashFile):String
+		{
+			return f.name;
+		});
 	}
 }
diff --git a/externs/air/sys/io/File.hx b/externs/air/sys/io/File.hx
index 55e659ffaa..64c9246228 100644
--- a/externs/air/sys/io/File.hx
+++ b/externs/air/sys/io/File.hx
@@ -1,5 +1,6 @@
 package sys.io;
 
+import openfl.utils.ByteArray;
 import flash.filesystem.File in FlashFile;
 import flash.filesystem.FileMode;
 import flash.filesystem.FileStream;
@@ -18,34 +19,63 @@ class File
 		return content;
 	}
 
-	public static function saveContent(path:String, content:String):Void {}
+	public static function saveContent(path:String, content:String):Void
+	{
+		var file = new FlashFile(path);
+		var stream = new FileStream();
+		stream.open(file, FileMode.WRITE);
+		stream.writeUTFBytes(content);
+		stream.close();
+	}
 
 	public static function getBytes(path:String):haxe.io.Bytes
 	{
-		return null;
+		var file = new FlashFile(path);
+		var stream = new FileStream();
+		stream.open(file, FileMode.READ);
+		var byteArray = new ByteArray();
+		stream.readBytes(byteArray, 0, stream.bytesAvailable);
+		stream.close();
+		var bytes:haxe.io.Bytes = byteArray;
+		return bytes;
 	}
 
-	public static function saveBytes(path:String, bytes:haxe.io.Bytes):Void {}
+	public static function saveBytes(path:String, bytes:haxe.io.Bytes):Void
+	{
+		var byteArray:ByteArray = bytes;
+		var file = new FlashFile(path);
+		var stream = new FileStream();
+		stream.open(file, FileMode.WRITE);
+		stream.writeBytes(byteArray);
+		stream.close();
+	}
 
 	public static function read(path:String, binary:Bool = true):FileInput
 	{
+		openfl.Lib.notImplemented();
 		return null;
 	}
 
 	public static function write(path:String, binary:Bool = true):FileOutput
 	{
+		openfl.Lib.notImplemented();
 		return null;
 	}
 
 	public static function append(path:String, binary:Bool = true):FileOutput
 	{
+		openfl.Lib.notImplemented();
 		return null;
 	}
 
 	public static function update(path:String, binary:Bool = true):FileOutput
 	{
+		openfl.Lib.notImplemented();
 		return null;
 	}
 
-	public static function copy(srcPath:String, dstPath:String):Void {}
+	public static function copy(srcPath:String, dstPath:String):Void
+	{
+		new FlashFile(srcPath).copyTo(new FlashFile(dstPath));
+	}
 }