diff --git a/test/test_packet.py b/test/test_packet.py
index 9349134ee..63d07d8db 100644
--- a/test/test_packet.py
+++ b/test/test_packet.py
@@ -14,35 +14,51 @@ from litex.soc.interconnect.packet import *
 
 from .test_stream import StreamPacket, stream_inserter, stream_collector, compare_packets
 
-packet_header_length = 31
-packet_header_fields = {
-    "field_8b"  : HeaderField(0,  0,   8),
-    "field_16b" : HeaderField(1,  0,  16),
-    "field_32b" : HeaderField(3,  0,  32),
-    "field_64b" : HeaderField(7,  0,  64),
-    "field_128b": HeaderField(15, 0, 128),
-}
-packet_header = Header(
-    fields           = packet_header_fields,
-    length           = packet_header_length,
-    swap_field_bytes = True)
-
-def packet_description(dw):
-    param_layout = packet_header.get_layout()
-    payload_layout = [("data", dw)]
-    return EndpointDescription(payload_layout, param_layout)
-
-def raw_description(dw):
-    payload_layout = [("data", dw)]
-    return EndpointDescription(payload_layout)
+def mask_last_be(dw, data, last_be):
+    masked_data = 0
 
+    for byte in range(dw // 8):
+        if 2**byte > last_be:
+            break
+        masked_data |= data & (0xFF << (byte * 8))
 
+    return masked_data
 
 class TestPacket(unittest.TestCase):
     def loopback_test(self, dw, seed=42, with_last_be=False, debug_print=False):
+        packet_header_length = 31
+        packet_header_fields = {
+            "field_8b"  : HeaderField(0,  0,   8),
+            "field_16b" : HeaderField(1,  0,  16),
+            "field_32b" : HeaderField(3,  0,  32),
+            "field_64b" : HeaderField(7,  0,  64),
+            "field_128b": HeaderField(15, 0, 128),
+        }
+        packet_header = Header(
+            fields           = packet_header_fields,
+            length           = packet_header_length,
+            swap_field_bytes = True)
+
+        def packet_description(dw):
+            param_layout = packet_header.get_layout()
+            payload_layout = [("data", dw)]
+
+            if with_last_be:
+                payload_layout += [("last_be", dw // 8)]
+
+            return EndpointDescription(payload_layout, param_layout)
+
+        def raw_description(dw):
+            payload_layout = [("data", dw)]
+
+            if with_last_be:
+                payload_layout += [("last_be", dw // 8)]
+
+            return EndpointDescription(payload_layout)
+
         prng = random.Random(seed)
         # Prepare packets
-        npackets = 8
+        npackets = 64
         packets  = []
         for n in range(npackets):
             header               = {}
@@ -56,10 +72,16 @@ class TestPacket(unittest.TestCase):
 
         class DUT(Module):
             def __init__(self):
-                self.submodules.packetizer = \
-                    Packetizer(packet_description(dw), raw_description(dw), packet_header)
-                self.submodules.depacketizer = \
-                    Depacketizer(raw_description(dw), packet_description(dw), packet_header)
+                self.submodules.packetizer = Packetizer(
+                    packet_description(dw),
+                    raw_description(dw),
+                    packet_header,
+                )
+                self.submodules.depacketizer = Depacketizer(
+                    raw_description(dw),
+                    packet_description(dw),
+                    packet_header,
+                )
                 self.comb += self.packetizer.source.connect(self.depacketizer.sink)
                 self.sink, self.source = self.packetizer.sink, self.depacketizer.source
 
@@ -102,11 +124,23 @@ class TestPacket(unittest.TestCase):
     def test_8bit_loopback(self):
         self.loopback_test(dw=8)
 
+    def test_8bit_loopback_last_be(self):
+        self.loopback_test(dw=8, with_last_be=True)
+
     def test_32bit_loopback(self):
         self.loopback_test(dw=32)
 
+    def test_32bit_loopback_last_be(self):
+        self.loopback_test(dw=32, with_last_be=True)
+
     def test_64bit_loopback(self):
         self.loopback_test(dw=64)
 
+    def test_64bit_loopback_last_be(self):
+        self.loopback_test(dw=64, with_last_be=True)
+
     def test_128bit_loopback(self):
         self.loopback_test(dw=128)
+
+    def test_128bit_loopback_last_be(self):
+        self.loopback_test(dw=128, with_last_be=True)