diff --git a/src/device.py b/src/device.py
index 7dbc663..cd75939 100644
--- a/src/device.py
+++ b/src/device.py
@@ -92,7 +92,11 @@ def handshake(self):
             self.write(0xA0)
             if self.read(1) == to_bytes(0x5F):
                 self.dev.flushInput()
+                self.dev.flushOutput()
                 break
+            self.dev.flushInput()
+            self.dev.flushOutput()
+
         #self.write(0xA0)
         #self.check(self.read(1), to_bytes(0x5F))