diff --git a/tests/functional/pyocf/types/cache.py b/tests/functional/pyocf/types/cache.py
index 4c6dd94..b5ece0f 100644
--- a/tests/functional/pyocf/types/cache.py
+++ b/tests/functional/pyocf/types/cache.py
@@ -569,7 +569,7 @@ class Cache:
     def free_device_config(self, cfg):
         lib = OcfLib.getInstance().ocf_volume_destroy(cfg._volume)
 
-    def attach_device(
+    def attach_device_async(
         self,
         device,
         force=False,
@@ -593,15 +593,40 @@ class Cache:
 
         self.write_lock()
 
-        c = OcfCompletion([("cache", c_void_p), ("priv", c_void_p), ("error", c_int)])
+        def callback(c):
+            self.write_unlock()
+            self.free_device_config(device_config)
+
+        c = OcfCompletion(
+            [("cache", c_void_p), ("priv", c_void_p), ("error", c_int)],
+            callback=callback
+        )
 
         self.owner.lib.ocf_mngt_cache_attach(self.cache_handle, byref(attach_cfg), c, None)
+
+        return c
+
+    def attach_device(
+        self,
+        device,
+        force=False,
+        perform_test=False,
+        cache_line_size=None,
+        open_cores=False,
+        disable_cleaner=False,
+    ):
+
+        c = self.attach_device_async(
+            device,
+            force,
+            perform_test,
+            cache_line_size,
+            open_cores,
+            disable_cleaner
+        )
+
         c.wait()
 
-        self.write_unlock()
-
-        self.free_device_config(device_config)
-
         if c.results["error"]:
             raise OcfError(
                 f"Attaching cache device failed",
diff --git a/tests/functional/pyocf/types/shared.py b/tests/functional/pyocf/types/shared.py
index a4cd19a..4f1c5de 100644
--- a/tests/functional/pyocf/types/shared.py
+++ b/tests/functional/pyocf/types/shared.py
@@ -83,7 +83,7 @@ class OcfCompletion:
             except KeyError:
                 raise KeyError(f"No completion argument {key} specified")
 
-    def __init__(self, completion_args: list, context=None):
+    def __init__(self, completion_args: list, context=None, callback=None):
         """
         Provide ctypes arg list, and optionally index of status argument in
         completion function which will be extracted (default - last argument).
@@ -95,6 +95,7 @@ class OcfCompletion:
         self.results = OcfCompletion.CompletionResult(completion_args)
         self._as_parameter_ = self.callback
         self.context = context
+        self.user_callback = callback
 
     @property
     def callback(self):
@@ -102,6 +103,8 @@ class OcfCompletion:
         def complete(*args):
             self.results.results = args
             self.e.set()
+            if self.user_callback:
+                self.user_callback(self)
 
         return complete
 
diff --git a/tests/functional/tests/engine/test_d2c.py b/tests/functional/tests/engine/test_d2c.py
index 5fb6710..f1a0fde 100644
--- a/tests/functional/tests/engine/test_d2c.py
+++ b/tests/functional/tests/engine/test_d2c.py
@@ -4,6 +4,7 @@
 #
 
 
+from time import sleep
 import pytest
 
 
@@ -18,7 +19,6 @@ from pyocf.utils import Size
 CORE_SIZE = 4096
 
 
-@pytest.mark.xfail(reason="Data corruption when switching from D2C")
 def test_d2c_io(pyocf_ctx):
     """
     Start cache in D2C
@@ -46,7 +46,8 @@ def test_d2c_io(pyocf_ctx):
     d2c_data.write(b"a" * CORE_SIZE, CORE_SIZE)
     d2c_io.set_data(d2c_data)
 
-    cache.attach_device(cache_device)
+    c = cache.attach_device_async(cache_device)
+    sleep(1)
 
     wt_io = vol.new_io(queue, 0, CORE_SIZE, IoDir.WRITE, 0, 0)
     wt_data = Data(CORE_SIZE)
@@ -55,11 +56,19 @@ def test_d2c_io(pyocf_ctx):
 
     wt_completion = Sync(wt_io).submit()
     assert int(wt_completion.results["err"]) == 0
-    assert cache.get_stats()["req"]["wr_full_misses"]["value"] == 1
 
     d2c_completion = Sync(d2c_io).submit()
     assert int(d2c_completion.results["err"]) == 0
-    assert cache.get_stats()["req"]["wr_pt"]["value"] == 1
+
+    c.wait()
+
+    if c.results["error"]:
+        raise OcfError(
+            f"Attaching cache device failed",
+            c.results["error"],
+        )
+
+    assert cache.get_stats()["req"]["wr_pt"]["value"] == 2
 
     read_io = vol.new_io(queue, 0, CORE_SIZE, IoDir.READ, 0, 0)
     read_data = Data(CORE_SIZE)
@@ -67,6 +76,7 @@ def test_d2c_io(pyocf_ctx):
 
     read_completion = Sync(read_io).submit()
     assert int(read_completion.results["err"]) == 0
+    assert cache.get_stats()["req"]["rd_full_misses"]["value"] == 1
 
     cache.stop()