diff --git a/modem/arq_session_irs.py b/modem/arq_session_irs.py
index 10c10142..875f055f 100644
--- a/modem/arq_session_irs.py
+++ b/modem/arq_session_irs.py
@@ -30,7 +30,6 @@ class ARQSessionIRS(arq_session.ARQSession):
 
         self.event_info_received = threading.Event()
         self.event_data_received = threading.Event()
-
         
         self.frame_factory = data_frame_factory.DataFrameFactory(self.config)
 
@@ -91,6 +90,7 @@ class ARQSessionIRS(arq_session.ARQSession):
             return False
         if not self.receive_data(): 
             return False
+        return True
 
     def run(self):
         self.set_state(self.STATE_WAITING_DATA)
@@ -141,11 +141,22 @@ class ARQSessionIRS(arq_session.ARQSession):
 
     def process_incoming_data(self):
         if self.received_frame['offset'] != self.received_bytes:
-            self.logger.info(f"Discarding data frame", frame=self.frame_received)
+            self.logger.info(f"Discarding data frame due to wrong offset", frame=self.frame_received)
             return False
 
-        self.received_data[self.received_frame['offset']:] = self.received_frame['data']
-        self.received_bytes += len(self.received_frame['data'])
+        remaining_data_length = len(self.receive_data) - self.received_bytes
+
+        # Is this the last data part?
+        if len(self.received_frame['data']) <= remaining_data_length:
+            # we only want the remaining length, not the entire frame data
+            data_part = self.received_frame['data'][:remaining_data_length]
+        else:
+            # we want the entire frame data
+            data_part = self.received_frame['data']
+
+        self.received_data[self.received_frame['offset']:] = data_part
+        self.received_bytes += len(data_part)
+
         return True
 
     def on_burst_ack_received(self, ack):
diff --git a/modem/arq_session_iss.py b/modem/arq_session_iss.py
index 24bd7e87..cc69e2b7 100644
--- a/modem/arq_session_iss.py
+++ b/modem/arq_session_iss.py
@@ -64,7 +64,7 @@ class ARQSessionISS(arq_session.ARQSession):
                 return True
             retries = retries - 1
 
-        self.setState(self.STATE_DISCONNECTED)
+        self.set_state(self.STATE_DISCONNECTED)
         return False
 
     def session_open(self):
diff --git a/modem/data_frame_factory.py b/modem/data_frame_factory.py
index c488222f..04030582 100644
--- a/modem/data_frame_factory.py
+++ b/modem/data_frame_factory.py
@@ -222,6 +222,15 @@ class DataFrameFactory:
         freedv = codec2.open_instance(mode.value)
         bytes_per_frame = int(codec2.api.freedv_get_bits_per_modem_frame(freedv) / 8)
         return bytes_per_frame
+    
+    def get_available_data_payload_for_mode(self, type: FR_TYPE, mode:codec2.FREEDV_MODE):
+        whole_frame_length = self.get_bytes_per_frame(mode)
+
+        available = whole_frame_length
+        for field, length in self.template_list[type.value].items():
+            if field != 'frame_length' and isinstance(length, int):
+                available -= length
+        return available
 
     def build_ping(self, destination):
         payload = {
diff --git a/modem/frame_dispatcher.py b/modem/frame_dispatcher.py
index 3fd30aa6..55dae01d 100644
--- a/modem/frame_dispatcher.py
+++ b/modem/frame_dispatcher.py
@@ -98,7 +98,7 @@ class DISPATCHER():
                 data['frequency_offset'],
             )
 
-    def new_process_data(self, bytes_out, freedv, bytes_per_frame: int, snr, offset) -> None:
+    def new_process_data(self, bytes_out, freedv, bytes_per_frame: int, snr, frequency_offset) -> None:
         # get frame as dictionary
         deconstructed_frame = self.frame_factory.deconstruct(bytes_out)
         frametype = deconstructed_frame["frame_type_int"]
@@ -116,7 +116,7 @@ class DISPATCHER():
                                 self.event_manager,
                                 self.modem_transmit_queue)
 
-        handler.handle(deconstructed_frame, snr, offset, freedv, bytes_per_frame)
+        handler.handle(deconstructed_frame, snr, frequency_offset, freedv, bytes_per_frame)
 
 
 
diff --git a/tests/test_arq_session.py b/tests/test_arq_session.py
index 305c5acf..668de4d7 100644
--- a/tests/test_arq_session.py
+++ b/tests/test_arq_session.py
@@ -72,7 +72,7 @@ class TestARQSession(unittest.TestCase):
     def testARQSession(self):
 
         # set Packet Error Rate (PER) / frame loss probability
-        self.loss_probability = 0
+        self.loss_probability = 50
 
         self.establishChannels()
         params = {
diff --git a/tests/test_data_frame_factory.py b/tests/test_data_frame_factory.py
index c49d4562..16004275 100755
--- a/tests/test_data_frame_factory.py
+++ b/tests/test_data_frame_factory.py
@@ -6,6 +6,7 @@ from config import CONFIG
 from data_frame_factory import DataFrameFactory
 from codec2 import FREEDV_MODE
 import helpers
+from modem_frametypes import FRAME_TYPE
 
 class TestDataFrameFactory(unittest.TestCase):
 
@@ -58,6 +59,10 @@ class TestDataFrameFactory(unittest.TestCase):
         payload = payload * 1000
         self.assertRaises(OverflowError, self.factory.build_arq_burst_frame,
             FREEDV_MODE.datac3, session_id, offset, payload)
+        
+    def testAvailablePayload(self):
+        avail = self.factory.get_available_data_payload_for_mode(FRAME_TYPE.BURST_FRAME, FREEDV_MODE.datac3)
+        self.assertEqual(avail, 123) # 128 bytes datac3 frame payload - BURST frame overhead
 
 if __name__ == '__main__':
     unittest.main()