diff --git a/Tools/autotest/arducopter.py b/Tools/autotest/arducopter.py
index f202f121b7..65af43f7d2 100644
--- a/Tools/autotest/arducopter.py
+++ b/Tools/autotest/arducopter.py
@@ -107,6 +107,8 @@ class AutoTestCopter(AutoTest):
         self.progress("WAITING FOR PARAMETERS")
         self.mavproxy.expect('Received [0-9]+ parameters')
 
+        self.get_mavlink_connection_going()
+
         self.apply_defaultfile_parameters()
 
         util.expect_setup_callback(self.mavproxy, self.expect_callback)
@@ -116,8 +118,6 @@ class AutoTestCopter(AutoTest):
 
         self.progress("Started simulator")
 
-        self.get_mavlink_connection_going()
-
         self.hasInit = True
         self.progress("Ready to start testing!")
 
diff --git a/Tools/autotest/ardusub.py b/Tools/autotest/ardusub.py
index 968088a0d0..0eb862c003 100644
--- a/Tools/autotest/ardusub.py
+++ b/Tools/autotest/ardusub.py
@@ -153,6 +153,15 @@ class AutoTestSub(AutoTest):
         if ex is not None:
             raise ex
 
+    def reboot_sitl(self):
+        """Reboot SITL instance and wait it to reconnect."""
+        self.mavproxy.send("reboot\n")
+        self.mavproxy.expect("Initialising APM")
+        # empty mav to avoid getting old timestamps:
+        while self.mav.recv_match(blocking=False):
+            pass
+        self.initialise_after_reboot_sitl()
+
     def autotest(self):
         """Autotest ArduSub in SITL."""
         self.check_test_syntax(test_file=os.path.realpath(__file__))
diff --git a/Tools/autotest/common.py b/Tools/autotest/common.py
index 396371de84..fa67b214d3 100644
--- a/Tools/autotest/common.py
+++ b/Tools/autotest/common.py
@@ -198,22 +198,33 @@ class AutoTest(ABC):
 
     def reboot_sitl(self):
         """Reboot SITL instance and wait it to reconnect."""
+        old_bootcount= self.get_parameter('STAT_BOOTCNT')
         self.mavproxy.send("reboot\n")
-        self.mavproxy.expect("Initialising APM")
-        # empty mav to avoid getting old timestamps:
-        if self.mav is not None:
-            while self.mav.recv_match(blocking=False):
+        tstart = self.get_sim_time()
+        while True:
+            if self.get_sim_time() - tstart > 10:
+                raise AutoTestTimeoutException("Did not detect reboot")
+            try:
+                if self.get_parameter('STAT_BOOTCNT', timeout=1) != old_bootcount:
+                    break
+            except NotAchievedException:
                 pass
+
+        # empty mav to avoid getting old timestamps:
+        while self.mav.recv_match(blocking=False):
+            pass
+
+        self.initialise_after_reboot_sitl()
+
+    def initialise_after_reboot_sitl(self):
+
         # after reboot stream-rates may be zero.  Prompt MAVProxy to
         # send a rate-change message by changing away from our normal
         # stream rates and back again:
-        if self.mav is not None:
-            tstart = self.get_sim_time()
+        tstart = self.get_sim_time()
         while True:
 
             self.mavproxy.send("set streamrate %u\n" % (self.sitl_streamrate()+1))
-            if self.mav is None:
-                break
 
             if self.get_sim_time() - tstart > 10:
                 raise AutoTestTimeoutException("SYSTEM_TIME not received")