diff --git a/common/file_reader.h b/common/file_reader.h
index bc4b7f66c..b53be4cca 100644
--- a/common/file_reader.h
+++ b/common/file_reader.h
@@ -207,7 +207,7 @@ class FileReader {
   }
   int ReadHex2() {
     int a = ReadHex1();
-    int b = ReadHex2();
+    int b = ReadHex1();
     if (a == -1 || b == -1) return -1;
     return (a << 4) | b;
   }