diff --git a/ledgerblue/ecWrapper.py b/ledgerblue/ecWrapper.py
index cb0f951..f36af18 100644
--- a/ledgerblue/ecWrapper.py
+++ b/ledgerblue/ecWrapper.py
@@ -64,7 +64,7 @@ def serialize(self, compressed=True):
                 out += self.obj.W.x.to_bytes(32, "big")
                 out += self.obj.W.y.to_bytes(32, "big")
             else:
-                out = b"\x03" if ((self.obj.W.y & 1) != 0) else "\x02"
+                out = b"\x03" if ((self.obj.W.y & 1) != 0) else b"\x02"
                 out += self.obj.W.x.to_bytes(32, "big")
             return out