diff --git a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java
index 3ec28f313..84c3956f7 100644
--- a/tools/dicttool/src/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java
+++ b/tools/dicttool/src/com/android/inputmethod/latin/dicttool/BinaryDictOffdeviceUtils.java
@@ -186,9 +186,7 @@ public final class BinaryDictOffdeviceUtils {
                 throw new UnsupportedFormatException("Header too large");
             }
             final byte[] headerBuffer = new byte[totalHeaderSize - tmpBuffer.length];
-            if (headerBuffer.length != input.read(headerBuffer)) {
-                throw new UnsupportedFormatException("File shorter than specified in the header");
-            }
+            readStreamExhaustively(input, headerBuffer);
             final HashMap<String, String> attributes =
                     BinaryDictDecoderUtils.decodeHeaderAttributes(headerBuffer);
             return new DictionaryHeader(totalHeaderSize, new DictionaryOptions(attributes),
@@ -196,6 +194,20 @@ public final class BinaryDictOffdeviceUtils {
         }
     }
 
+    private static void readStreamExhaustively(final InputStream inputStream,
+            final byte[] outBuffer) throws IOException, UnsupportedFormatException {
+        int readBytes = 0;
+        int readBytesLastCycle = -1;
+        while (readBytes != outBuffer.length) {
+            readBytesLastCycle = inputStream.read(outBuffer, readBytes,
+                    outBuffer.length - readBytes);
+            if (readBytesLastCycle == -1)
+                throw new UnsupportedFormatException("File shorter than specified in the header"
+                        + " (expected " + outBuffer.length + ", read " + readBytes + ")");
+            readBytes += readBytesLastCycle;
+        }
+    }
+
     public static void copy(final InputStream input, final OutputStream output) throws IOException {
         final byte[] buffer = new byte[COPY_BUFFER_SIZE];
         for (int readBytes = input.read(buffer); readBytes >= 0; readBytes = input.read(buffer)) {