diff --git a/src/openmv/camera.py b/src/openmv/camera.py
index fd1aa20..414fb19 100644
--- a/src/openmv/camera.py
+++ b/src/openmv/camera.py
@@ -7,6 +7,7 @@
 # This module provides the high-level Camera class that handles all
 # camera operations and channel communications using the OpenMV Protocol.
 
+import time
 import struct
 import sys
 import serial
@@ -329,15 +330,24 @@ def update_capabilities(self):
         self._send_cmd_wait_resp(Opcode.PROTO_SET_CAPS, 0, payload)
 
     @retry_if_failed
-    def stop(self):
-        """Stop running script"""
+    def stop(self, timeout=None):
+        """Stop running script and wait for it to exit"""
         # Stop running script
         stdin_id = self.get_channel(name="stdin")
         self._channel_ioctl(stdin_id, ChannelIOCTL.STDIN_STOP)
+        # Wait for the script to exit
+        timeout = self.timeout if timeout is None else timeout
+        start_time = time.time()
+        while self.read_status()["stdin"]:
+            if time.time() - start_time > timeout:
+                raise TimeoutException("Timeout waiting for the script to stop")
 
     @retry_if_failed
     def exec(self, script):
         """Write and execute a script"""
+        # Stop the running script first
+        if self.read_status()["stdin"]:
+            self.stop()
         stdin_id = self.get_channel(name="stdin")
         # Reset script buffer
         self._channel_ioctl(stdin_id, ChannelIOCTL.STDIN_RESET)
diff --git a/src/openmv/transport.py b/src/openmv/transport.py
index c0121f5..6f72202 100644
--- a/src/openmv/transport.py
+++ b/src/openmv/transport.py
@@ -215,7 +215,6 @@ def recv_packet(self, poll_events=False):
             if packet['flags'] & Flags.EVENT:
                 self.event_callback(packet['channel'], 0xFFFF if not packet['length']
                                     else struct.unpack('<H', packet['payload'])[0])
-                start_time = time.time()
                 continue
 
             # Update sequence after each packet (including fragments)
@@ -279,12 +278,13 @@ def _process(self):
                 if length > self.max_payload:
                     self.log(seq, chan, opcode, flags, length, "Rjct")
                     self.buf.consume(1)
-                elif not self._check_seq(seq, self.sequence, opcode, flags):
+                elif not self._check_crc(crc, header[:Protocol.HEADER_SIZE - 2], 16):
                     self.log(seq, chan, opcode, flags, length, "Rjct")
                     self.buf.consume(1)
-                elif not self._check_crc(crc, header[:Protocol.HEADER_SIZE - 2], 16):
+                elif not self._check_seq(seq, self.sequence, opcode, flags):
                     self.log(seq, chan, opcode, flags, length, "Rjct")
                     self.buf.consume(1)
+                    raise SequenceException("")
                 else:
                     self.state = State.PAYLOAD
                     self.plength = Protocol.HEADER_SIZE + length