diff --git a/test/functional/api/cas/cache.py b/test/functional/api/cas/cache.py
index 247d2ba9d..a5b6d373d 100644
--- a/test/functional/api/cas/cache.py
+++ b/test/functional/api/cas/cache.py
@@ -1,6 +1,6 @@
 #
 # Copyright(c) 2019-2021 Intel Corporation
-# Copyright(c) 2024-2025 Huawei Technologies Co., Ltd.
+# Copyright(c) 2024-2026 Huawei Technologies Co., Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -30,7 +30,7 @@
 from connection.utils.output import Output
 from storage_devices.device import Device
 from test_tools.os_tools import sync
-from type_def.size import Size
+from type_def.size import Size, Unit
 
 
 class Cache:
@@ -210,7 +210,11 @@ def set_params_alru(self, alru_params: FlushParametersAlru) -> Output:
                 else None
             ),
             (alru_params.dirty_ratio_threshold if alru_params.dirty_ratio_threshold else None),
-            (alru_params.dirty_ratio_inertia if alru_params.dirty_ratio_inertia else None),
+            (
+                int(alru_params.dirty_ratio_inertia.get_value(Unit.MebiByte))
+                if alru_params.dirty_ratio_inertia
+                else None
+            ),
         )
 
     def set_promotion_policy(self, policy: PromotionPolicy) -> Output:
diff --git a/test/functional/api/cas/casadm.py b/test/functional/api/cas/casadm.py
index 0fecccb52..6fe1dd7ac 100644
--- a/test/functional/api/cas/casadm.py
+++ b/test/functional/api/cas/casadm.py
@@ -1,6 +1,6 @@
 #
 # Copyright(c) 2019-2022 Intel Corporation
-# Copyright(c) 2024-2025 Huawei Technologies Co., Ltd.
+# Copyright(c) 2024-2026 Huawei Technologies Co., Ltd.
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -187,7 +187,7 @@ def set_param_cleaning_alru(
     flush_max_buffers: int | None = None,
     activity_threshold: int | None = None,
     dirty_ratio_threshold: int | None = None,
-    dirty_ratio_inertia: Size | None = None,
+    dirty_ratio_inertia: int | None = None,
     shortcut: bool = False,
 ) -> Output:
     _wake_up = str(wake_up) if wake_up is not None else None
@@ -195,7 +195,7 @@ def set_param_cleaning_alru(
     _flush_max_buffers = str(flush_max_buffers) if flush_max_buffers is not None else None
     _activity_threshold = str(activity_threshold) if activity_threshold is not None else None
     _dirty_ratio_threshold = str(dirty_ratio_threshold) if dirty_ratio_threshold is not None else None
-    _dirty_ratio_inertia = str(dirty_ratio_inertia.get_value(Unit.MebiByte)) if dirty_ratio_inertia is not None else None
+    _dirty_ratio_inertia = str(dirty_ratio_inertia) if dirty_ratio_inertia is not None else None
     output = TestRun.executor.run(
         set_param_cleaning_alru_cmd(
             cache_id=str(cache_id),
diff --git a/test/functional/api/cas/ioclass_config.py b/test/functional/api/cas/ioclass_config.py
index 3326dab7b..37c674ee5 100644
--- a/test/functional/api/cas/ioclass_config.py
+++ b/test/functional/api/cas/ioclass_config.py
@@ -1,6 +1,7 @@
 #
 # Copyright(c) 2019-2022 Intel Corporation
 # Copyright(c) 2024-2025 Huawei Technologies Co., Ltd.
+# Copyright(c) 2026 Unvertical
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -166,7 +167,9 @@ def set_random_rule(self):
             "file_offset",
             "request_size",
         ]
-        if get_kernel_version() >= version.Version("4.13"):
+        if (version.Version("4.13") <= get_kernel_version() <= version.Version("5.17") or
+            version.Version("6.9") <= get_kernel_version()
+        ):
             rules.append("wlth")
 
         rule = random.choice(rules)
diff --git a/test/functional/tests/cache_ops/test_seq_cutoff.py b/test/functional/tests/cache_ops/test_seq_cutoff.py
index ae76a292c..9dbb6671d 100644
--- a/test/functional/tests/cache_ops/test_seq_cutoff.py
+++ b/test/functional/tests/cache_ops/test_seq_cutoff.py
@@ -1,6 +1,7 @@
 #
 # Copyright(c) 2019-2021 Intel Corporation
 # Copyright(c) 2024-2025 Huawei Technologies Co., Ltd.
+# Copyright(c) 2026 Unvertical
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -407,7 +408,7 @@ def test_seq_cutoff_thresh_fill(cache_line_size, io_dir):
         fio_additional_size = Size(10, Unit.Blocks4096)
         threshold = Size.generate_random_size(
             min_size=1,
-            max_size=SEQ_CUTOFF_THRESHOLD_MAX.get_value(Unit.KibiByte),
+            max_size=int(SEQ_CUTOFF_THRESHOLD_MAX.get_value(Unit.KibiByte)),
             unit=Unit.KibiByte,
         )
         io_size = (threshold + fio_additional_size).align_down(0x1000)
diff --git a/test/functional/tests/stats/test_consistency_between_outputs.py b/test/functional/tests/stats/test_consistency_between_outputs.py
index 4fb993007..417c246ed 100644
--- a/test/functional/tests/stats/test_consistency_between_outputs.py
+++ b/test/functional/tests/stats/test_consistency_between_outputs.py
@@ -1,6 +1,7 @@
 #
 # Copyright(c) 2020-2021 Intel Corporation
 # Copyright(c) 2024-2025 Huawei Technologies Co., Ltd.
+# Copyright(c) 2026 Unvertical
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
@@ -15,7 +16,7 @@
 from core.test_run import TestRun
 from storage_devices.disk import DiskType, DiskTypeSet, DiskTypeLowerThan
 from test_tools.dd import Dd
-from test_utils.size import Size, Unit
+from type_def.size import Size, Unit
 
 iterations = 4
 cache_size = Size(4, Unit.GibiByte)