diff --git a/pydivert/packet/header.py b/pydivert/packet/header.py
index bdeb21a..ab67900 100644
--- a/pydivert/packet/header.py
+++ b/pydivert/packet/header.py
@@ -48,9 +48,9 @@ def raw(self) -> memoryview:
     @raw.setter
     def raw(self, val: bytes | bytearray | memoryview) -> None:
         if len(val) == len(self.raw):
-            self.raw[:] = val  # pragma: no cover
+            self.raw[:] = val
         else:
-            self._packet.raw = memoryview(bytearray(self._packet.raw[: self._start].tobytes() + val))
+            self._packet.raw = memoryview(bytearray(self._packet.raw[: self._start].tobytes() + bytes(val)))
             if self._packet.ip:
                 self._packet.ip.packet_len = len(self._packet.raw)
         self._packet._invalidate_checksums()
@@ -81,9 +81,9 @@ def payload(self) -> bytes:
     @payload.setter
     def payload(self, val: bytes | bytearray | memoryview) -> None:
         if len(val) == len(self.raw) - self.header_len:
-            self.raw[self.header_len :] = val  # pragma: no cover
+            self.raw[self.header_len :] = val
         else:
-            self.raw = self.raw[: self.header_len].tobytes() + val
+            self.raw = self.raw[: self.header_len].tobytes() + bytes(val)
 
 
 class PortMixin(RawProtocol):
@@ -92,19 +92,19 @@ def src_port(self) -> int:
         """
         The source port.
         """
-        return struct.unpack_from("!H", self.raw, 0)[0]  # pragma: no cover
+        return struct.unpack_from("!H", self.raw, 0)[0]
 
     @src_port.setter
     def src_port(self, val: int) -> None:
-        self.raw[0:2] = struct.pack("!H", val)  # pragma: no cover
+        self.raw[0:2] = struct.pack("!H", val)
 
     @property
     def dst_port(self) -> int:
         """
         The destination port.
         """
-        return struct.unpack_from("!H", self.raw, 2)[0]  # pragma: no cover
+        return struct.unpack_from("!H", self.raw, 2)[0]
 
     @dst_port.setter
     def dst_port(self, val: int) -> None:
-        self.raw[2:4] = struct.pack("!H", val)  # pragma: no cover
+        self.raw[2:4] = struct.pack("!H", val)
diff --git a/pydivert/tests/test_packet.py b/pydivert/tests/test_packet.py
index 3840672..7c11ea7 100644
--- a/pydivert/tests/test_packet.py
+++ b/pydivert/tests/test_packet.py
@@ -232,3 +232,57 @@ def test_ipv4_hypo(src, dst):
     p.dst_addr = dst
     assert p.src_addr == src
     assert p.dst_addr == dst
+
+
+def test_header_raw_modification():
+    p = create_base_ipv4_tcp()
+    assert p.ipv4 is not None
+    original_len = len(p.ipv4.raw)
+
+    # same length
+    new_raw = bytearray([0x12] * original_len)
+    p.ipv4.raw = new_raw
+    assert bytes(p.ipv4.raw) == new_raw
+
+    # different length
+    p = create_base_ipv4_tcp()
+    assert p.ipv4 is not None
+    new_raw = bytearray([0x45, 0x00, 0x00, 0x29] + [0x34] * (original_len - 4 + 1))
+    p.ipv4.raw = new_raw
+    assert p.ipv4.packet_len == len(p.raw)
+    assert getattr(p, "_ip_checksum", False) is False
+
+    # PayloadMixin and PortMixin
+
+    from pydivert.packet.header import PayloadMixin, PortMixin
+
+    class DummyProtocol(PortMixin, PayloadMixin):
+        def __init__(self):
+            self._raw = bytearray([0] * 20)
+
+        @property
+        def raw(self):
+            return memoryview(self._raw)
+
+        @raw.setter
+        def raw(self, val):
+            self._raw = bytearray(val)
+
+        @property
+        def header_len(self):
+            return 8
+
+    proto = DummyProtocol()
+    assert proto.src_port == 0
+    proto.src_port = 80
+    assert proto.src_port == 80
+    assert proto.dst_port == 0
+    proto.dst_port = 8080
+    assert proto.dst_port == 8080
+    assert len(proto.payload) == 12
+    proto.payload = bytearray([1] * 12)
+    assert len(proto.payload) == 12
+    assert proto.payload[0] == 1
+    proto.payload = bytearray([2] * 10)
+    assert len(proto.payload) == 10
+    assert proto.payload[0] == 2