diff --git a/UNITTESTS/features/cellular/framework/device/athandler/athandlertest.cpp b/UNITTESTS/features/cellular/framework/device/athandler/athandlertest.cpp
index 6b8b414..a48c018 100644
--- a/UNITTESTS/features/cellular/framework/device/athandler/athandlertest.cpp
+++ b/UNITTESTS/features/cellular/framework/device/athandler/athandlertest.cpp
@@ -25,7 +25,6 @@
 #include "mbed_poll_stub.h"
 #include "CellularUtil_stub.h"
 
-#include "Timer_stub.h"
 
 using namespace mbed;
 using namespace events;
@@ -228,7 +227,6 @@
     at.process_oob();
 
     at.clear_error();
-    timer_stub_value = 0;
     filehandle_stub_table_pos = 0;
     at.read_bytes(buf, 5);
 
@@ -244,7 +242,6 @@
     filehandle_stub_table = table2;
 
     at.clear_error();
-    timer_stub_value = 0;
     filehandle_stub_table_pos = 0;
     mbed_poll_stub::revents_value = POLLIN;
     mbed_poll_stub::int_value = 1;
diff --git a/UNITTESTS/features/cellular/framework/device/athandler/unittest.cmake b/UNITTESTS/features/cellular/framework/device/athandler/unittest.cmake
index 060b14a..26c8058 100644
--- a/UNITTESTS/features/cellular/framework/device/athandler/unittest.cmake
+++ b/UNITTESTS/features/cellular/framework/device/athandler/unittest.cmake
@@ -28,7 +28,6 @@
   stubs/SerialBase_stub.cpp
   stubs/mbed_assert_stub.cpp
   stubs/mbed_poll_stub.cpp
-  stubs/Timer_stub.cpp
   stubs/equeue_stub.c
   stubs/Kernel_stub.cpp
   stubs/ThisThread_stub.cpp
diff --git a/UNITTESTS/platform/ATCmdParser/test_ATCmdParser.cpp b/UNITTESTS/platform/ATCmdParser/test_ATCmdParser.cpp
index 535aa19..dbe81c5 100644
--- a/UNITTESTS/platform/ATCmdParser/test_ATCmdParser.cpp
+++ b/UNITTESTS/platform/ATCmdParser/test_ATCmdParser.cpp
@@ -23,7 +23,6 @@
 #include <stdarg.h>
 #include "FileHandle_stub.h"
 #include "mbed_poll_stub.h"
-#include "Timer_stub.h"
 
 using namespace mbed;
 
@@ -110,7 +109,6 @@
     at.process_oob();
     expected_oob_callback = false;
 
-    timer_stub_value = 0;
     filehandle_stub_table_pos = 0;
     at.read(buf, 5);
 
@@ -127,7 +125,6 @@
     table2[4] = 0;
     filehandle_stub_table = table2;
 
-    timer_stub_value = 0;
     filehandle_stub_table_pos = 0;
     mbed_poll_stub::revents_value = POLLIN;
     mbed_poll_stub::int_value = 1;
diff --git a/UNITTESTS/stubs/Timer_stub.cpp b/UNITTESTS/stubs/Timer_stub.cpp
deleted file mode 100644
index 2e20c16..0000000
--- a/UNITTESTS/stubs/Timer_stub.cpp
+++ /dev/null
@@ -1,74 +0,0 @@
-/*
- * Copyright (c) , Arm Limited and affiliates.
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include "Timer.h"
-#include "Timer_stub.h"
-
-namespace mbed {
-
-Timer::Timer()
-{
-}
-
-Timer::Timer(const ticker_data_t *data)
-{
-}
-
-Timer::~Timer()
-{
-}
-
-void Timer::start()
-{
-}
-
-void Timer::stop()
-{
-    ;
-}
-
-int Timer::read_us()
-{
-    return 0;
-}
-
-float Timer::read()
-{
-    return 0;
-}
-
-int Timer::read_ms()
-{
-    timer_stub_value += timer_stub_step;
-    return timer_stub_value;
-}
-
-us_timestamp_t Timer::read_high_resolution_us()
-{
-    return 0;
-}
-
-void Timer::reset()
-{
-}
-
-Timer::operator float()
-{
-    return 0;
-}
-
-} // namespace mbed
diff --git a/UNITTESTS/stubs/Timer_stub.h b/UNITTESTS/stubs/Timer_stub.h
deleted file mode 100644
index a97333f..0000000
--- a/UNITTESTS/stubs/Timer_stub.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (c) , Arm Limited and affiliates.
- * SPDX-License-Identifier: Apache-2.0
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef TIMER_STUB_H
-#define TIMER_STUB_H
-
-
-static uint16_t timer_stub_value = 0;
-static uint16_t timer_stub_step = 20;
-
-#endif
diff --git a/drivers/Timeout.h b/drivers/Timeout.h
index 52a46de..da703e9 100644
--- a/drivers/Timeout.h
+++ b/drivers/Timeout.h
@@ -97,9 +97,6 @@
     /** Clock to use with attach_absolute, guaranteeing running only while attached or manually locked */
     using clock = HighResClock;
 
-    /** Clock to use with attach_absolute, running always */
-    using steady_clock = SteadyHighResClock;
-
     /** @copydoc TimeoutBase::scheduled_time() */
     HighResClock::time_point scheduled_time() const
     {
diff --git a/drivers/source/Timeout.cpp b/drivers/source/Timeout.cpp
index d890e0e..daed37e 100644
--- a/drivers/source/Timeout.cpp
+++ b/drivers/source/Timeout.cpp
@@ -44,9 +44,7 @@
  * (In C++17 could avoid the need for this by making the members inline).
  */
 const bool HighResClock::is_steady;
-const bool SteadyHighResClock::is_steady;
 const bool LowPowerClock::is_steady;
-mstd::once_flag SteadyHighResClock::init;
 const bool RealTimeClock::is_steady;
 
 #if DEVICE_LPTICKER
diff --git a/rtos/ConditionVariable.h b/rtos/ConditionVariable.h
index cb6e56b..d602d7c 100644
--- a/rtos/ConditionVariable.h
+++ b/rtos/ConditionVariable.h
@@ -28,6 +28,7 @@
 #include "rtos/mbed_rtos_types.h"
 #include "rtos/Mutex.h"
 #include "rtos/Semaphore.h"
+#include "rtos/Kernel.h"
 
 #include "platform/NonCopyable.h"