diff --git a/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java b/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
index 89a06e4a..e63609c0 100644
--- a/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
+++ b/dexlib2/src/main/java/org/jf/dexlib2/writer/DexFile.java
@@ -233,7 +233,7 @@ public class DexFile {
     }
 
     private static DexWriter outputAt(RandomAccessFile raf, int filePosition) throws IOException {
-        return new DexWriter(new RandomAccessFileOutputStream(raf), filePosition);
+        return new DexWriter(new RandomAccessFileOutputStream(raf, filePosition), filePosition);
     }
 
     public static void writeTo(@Nonnull String path, @Nonnull org.jf.dexlib2.iface.DexFile input) throws IOException {
diff --git a/util/src/main/java/org/jf/util/RandomAccessFileOutputStream.java b/util/src/main/java/org/jf/util/RandomAccessFileOutputStream.java
index cabe6768..b804d265 100644
--- a/util/src/main/java/org/jf/util/RandomAccessFileOutputStream.java
+++ b/util/src/main/java/org/jf/util/RandomAccessFileOutputStream.java
@@ -37,21 +37,29 @@ import java.io.OutputStream;
 import java.io.RandomAccessFile;
 
 public class RandomAccessFileOutputStream extends OutputStream {
+    private int filePosition;
     @Nonnull private final RandomAccessFile raf;
 
-    public RandomAccessFileOutputStream(@Nonnull RandomAccessFile raf) {
+    public RandomAccessFileOutputStream(@Nonnull RandomAccessFile raf, int startFilePosition) {
+        this.filePosition = startFilePosition;
         this.raf = raf;
     }
 
     @Override public void write(int b) throws IOException {
+        raf.seek(filePosition);
+        filePosition++;
         raf.write(b);
     }
 
     @Override public void write(byte[] b) throws IOException {
+        raf.seek(filePosition);
+        filePosition += b.length;
         raf.write(b);
     }
 
     @Override public void write(byte[] b, int off, int len) throws IOException {
+        raf.seek(filePosition);
+        filePosition += len;
         raf.write(b, off, len);
     }
 }