diff --git a/python/serial.py b/python/serial.py
index 0e1a3de..72ab3de 100644
--- a/python/serial.py
+++ b/python/serial.py
@@ -19,7 +19,10 @@ class PandaSerial(object):
   def write(self, dat):
     #print "W: ", dat.encode("hex")
     #print '  pigeon_send("' + ''.join(map(lambda x: "\\x%02X" % ord(x), dat)) + '");'
-    return self.panda.serial_write(self.port, str.encode(dat))
+    if(isinstance(dat, bytes)):
+      return self.panda.serial_write(self.port, dat)
+    else:
+      return self.panda.serial_write(self.port, str.encode(dat))
 
   def close(self):
     pass