diff --git a/artiq/compiler/targets.py b/artiq/compiler/targets.py
index 22c1e9a2b..ffdb7d994 100644
--- a/artiq/compiler/targets.py
+++ b/artiq/compiler/targets.py
@@ -33,9 +33,9 @@ class RunTool:
         stdout, stderr = process.communicate()
         if process.returncode != 0:
             raise Exception("{} invocation failed: {}".
-                            format(cmdline[0], stderr.decode('utf-8')))
+                            format(cmdline[0], stderr))
 
-        self._tempfiles["__stdout__"] = io.StringIO(stdout.decode('utf-8'))
+        self._tempfiles["__stdout__"] = io.StringIO(stdout)
         for key in self._tempdata:
             if self._tempdata[key] is None:
                 self._tempfiles[key] = open(self._tempnames[key], "rb")