diff --git a/tests/test_protect_call.py b/tests/test_protect_call.py
index db32a2f42..0ad07fb75 100644
--- a/tests/test_protect_call.py
+++ b/tests/test_protect_call.py
@@ -1,3 +1,4 @@
+import time
 import unittest
 import common
 
@@ -10,7 +11,7 @@ class TestProtectCall(common.TrezorTest):
         entropy_len = 10
         entropy = self.client.get_entropy(entropy_len)
         self.assertEqual(len(entropy), entropy_len)
-        
+
     def test_no_protection(self):
         self.client.load_device(seed=self.mnemonic1, pin='')
         
@@ -30,6 +31,37 @@ class TestProtectCall(common.TrezorTest):
     def test_cancelled_pin(self):
         self.client.setup_debuglink(button=True, pin_correct=-1)  # PIN cancel
         self.assertRaises(PinException, self._some_protected_call)
+
+    def test_exponential_backoff_with_reboot(self):
+        self.client.setup_debuglink(button=True, pin_correct=False)
         
+        def test_backoff(attempts, start):
+            expected = 1.8 ** attempts
+            got = time.time() - start
+
+            msg = "Pin delay expected to be at least %s seconds, got %s" % (expected, got)
+            print msg
+            self.assertLessEqual(expected, got, msg)
+
+        for attempt in range(1, 6):
+            start = time.time()
+            self.assertRaises(PinException, self._some_protected_call)
+            test_backoff(attempt, start)
+
+        # Unplug Trezor now
+        self.client.debuglink.stop()
+        self.client.close()
+
+        # Give it some time to reboot (it may take some time on RPi)
+        boot_delay = 5
+        start = time.time()
+        time.sleep(boot_delay)
+
+        # Connect to Trezor again
+        self.setUp()
+        print "Expected reboot time %s seconds" % (1.8 ** attempt)
+        print "Rebooted in %s seconds" % (time.time() - start)
+        self.assertLessEqual(1.8 ** attempt, time.time() - start, "Bootup took less than expected!")
+
 if __name__ == '__main__':
     unittest.main()
diff --git a/trezorlib/client.py b/trezorlib/client.py
index ccb058c53..0d28cf1a6 100644
--- a/trezorlib/client.py
+++ b/trezorlib/client.py
@@ -41,7 +41,12 @@ class TrezorClient(object):
     def init_device(self):
         self.master_public_key = None
         self.features = self.call(proto.Initialize())
-        
+
+    def close(self):
+        self.transport.close()
+        if self.debuglink:
+            self.debuglink.transport.close()
+
     def get_master_public_key(self):
         if self.master_public_key:
             return self.master_public_key
diff --git a/trezorlib/debuglink.py b/trezorlib/debuglink.py
index d32f7cbcf..0c7dc550d 100644
--- a/trezorlib/debuglink.py
+++ b/trezorlib/debuglink.py
@@ -45,4 +45,7 @@ class DebugLink(object):
         self.press_button(True)
     
     def press_no(self):
-        self.press_button(False)
\ No newline at end of file
+        self.press_button(False)
+
+    def stop(self):
+        self.transport.write(proto.DebugLinkStop())