diff --git a/satcom/openlst/client_packet_lib.py b/satcom/openlst/client_packet_lib.py
index 1347e1c..8f20427 100644
--- a/satcom/openlst/client_packet_lib.py
+++ b/satcom/openlst/client_packet_lib.py
@@ -15,8 +15,8 @@ class ClientPacketHeader(BaseModel):
 
     def err(self):
         """Throws an error if any params are out of bounds"""
-        if self.length < 6 or self.length > 251:
-            return ValueError('length must be 6-251')
+        if self.length < 7 or self.length > 251:
+            return ValueError('length must be 7-251')
         if self.hardware_id < 0 or self.hardware_id > 65535:
             return ValueError('hardware_id must be 0-65535')
         if self.sequence_number < 0 or self.sequence_number > 65535:
diff --git a/satcom/openlst/space_packet_lib.py b/satcom/openlst/space_packet_lib.py
index 792f4fc..a253702 100644
--- a/satcom/openlst/space_packet_lib.py
+++ b/satcom/openlst/space_packet_lib.py
@@ -19,8 +19,8 @@ class SpacePacketHeader(BaseModel):
 
     def err(self):
         """Throws an error if any params are out of bounds"""
-        if self.length < 9 or self.length > 251:
-            return ValueError('length must be 9-251')
+        if self.length < 10 or self.length > 254:
+            return ValueError('length must be 10-254')
         if self.sequence_number < 0 or self.sequence_number > 65535:
             return ValueError('sequence_number must be 0-65535')
         if self.destination < 0 or self.destination > 255:
diff --git a/satcom/openlst/test_client_packet.py b/satcom/openlst/test_client_packet.py
index ae6f897..dc51226 100644
--- a/satcom/openlst/test_client_packet.py
+++ b/satcom/openlst/test_client_packet.py
@@ -82,5 +82,4 @@ def test_client_packet_from_bytes_empty_frame(self):
         p = client_pkt_lib.ClientPacket(val)
         pkt = p.from_bytes(val)
 
-        self.assertIsNone(pkt.err(), msg=f'{pkt.header.length}')
-        self.assertEqual(len(pkt.data), 0, f'expected empty result, got {pkt.data}')
+        self.assertIsNotNone(pkt.err())