diff --git a/src/build/file2str.py b/src/build/file2str.py
index 7a6de5b11c5..18045560226 100644
--- a/src/build/file2str.py
+++ b/src/build/file2str.py
@@ -40,7 +40,7 @@ try:
             chunk = src.read(16)
             if chunk:
                 for b in chunk:
-                    dst.write('0x%02x' % b)
+                    dst.write('0x%02x' % ord(b))
                     offs = offs + 1
                     if offs != byteCount:
                         dst.write(',')