diff --git a/test/py/tests/test_fit.py b/test/py/tests/test_fit.py
index a0f9350..34696e9 100755
--- a/test/py/tests/test_fit.py
+++ b/test/py/tests/test_fit.py
@@ -143,7 +143,7 @@
         Returns:
             Contents of file as a string
         """
-        with open(fname, 'r') as fd:
+        with open(fname, 'rb') as fd:
             return fd.read()
 
     def make_dtb():