diff --git a/.gitignore b/.gitignore
index deb1de7..3e907cf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -102,3 +102,5 @@
 CMakeCache.txt
 cmake_install.cmake
 CMakeFiles/
+cmake_build/
+Testing/
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63c80e8..4b447a7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,8 +5,10 @@
 
 cmake_minimum_required(VERSION 3.19.0 FATAL_ERROR)
 
-include(${MBED_CONFIG_PATH}/mbed_config.cmake)
-include(mbed_set_linker_script)
+if(${CMAKE_CROSSCOMPILING})
+    include(${MBED_CONFIG_PATH}/mbed_config.cmake)
+    include(mbed_set_linker_script)
+endif()
 
 project(mbed-os)
 
@@ -15,6 +17,18 @@
     "${mbed-os_SOURCE_DIR}/platform/FEATURE_EXPERIMENTAL_API/FEATURE_PSA/TARGET_TFM/TARGET_TFM_LATEST/scripts;${mbed-os_SOURCE_DIR}/targets/TARGET_Cypress/scripts;${mbed-os_SOURCE_DIR}/targets/TARGET_NXP/scripts"
 )
 
+option(BUILD_TESTING "Run unit tests only." OFF)
+
+if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
+    include(CTest)   
+    add_subdirectory(UNITTESTS)
+    # Add MBED_TEST_MODE for backward compatibility with Greentea tests written for use with Mbed CLI 1
+    target_compile_definitions(${PROJECT_NAME}
+        PUBLIC
+            MBED_TEST_MODE
+    )
+endif()
+
 add_library(mbed-core INTERFACE)
 
 add_library(mbed-os INTERFACE)
@@ -33,88 +47,83 @@
 )
 # Validate selected C library type
 # The C library type selected has to match the library that the target can support
-if(${MBED_C_LIB} STREQUAL "small")
-    if(NOT "small" IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
-        if("std" IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
-            message(WARNING
-                "We noticed that target.c_lib is set to `${MBED_C_LIB}`."
-                " As the ${MBED_TARGET} target does not support a small C library for the ${MBED_TOOLCHAIN} toolchain,"
-                " we are using the standard C library instead."
-            )
-            set(MBED_C_LIB "std" CACHE STRING "")
+if(${CMAKE_CROSSCOMPILING})
+    if(${MBED_C_LIB} STREQUAL "small")
+        if(NOT "small" IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
+            if("std" IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
+                message(WARNING
+                    "We noticed that target.c_lib is set to `${MBED_C_LIB}`."
+                    " As the ${MBED_TARGET} target does not support a small C library for the ${MBED_TOOLCHAIN} toolchain,"
+                    " we are using the standard C library instead."
+                )
+                set(MBED_C_LIB "std" CACHE STRING "")
+            endif()
         endif()
+    elseif(NOT ${MBED_C_LIB} IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
+        message(FATAL_ERROR
+            "Invalid `target.c_lib` ('${MBED_C_LIB}') for '${MBED_TARGET}' target."
+            "\nPossible value(s): ${MBED_TARGET_SUPPORTED_C_LIBS}"
+        )
     endif()
-elseif(NOT ${MBED_C_LIB} IN_LIST MBED_TARGET_SUPPORTED_C_LIBS)
-    message(FATAL_ERROR
-        "Invalid `target.c_lib` ('${MBED_C_LIB}') for '${MBED_TARGET}' target."
-        "\nPossible value(s): ${MBED_TARGET_SUPPORTED_C_LIBS}"
-    )
-endif()
 
-# Validate selected printf library
-set(MBED_PRINTF_LIB_TYPES std minimal-printf)
-if(NOT ${MBED_PRINTF_LIB} IN_LIST MBED_PRINTF_LIB_TYPES)
-    message(FATAL_ERROR
-        "Invalid printf library type '${MBED_PRINTF_LIB}'. Possible values:\n ${MBED_PRINTF_LIB_TYPES}"
-    )
-endif()
+    # Validate selected printf library
+    set(MBED_PRINTF_LIB_TYPES std minimal-printf)
+    if(NOT ${MBED_PRINTF_LIB} IN_LIST MBED_PRINTF_LIB_TYPES)
+        message(FATAL_ERROR
+            "Invalid printf library type '${MBED_PRINTF_LIB}'. Possible values:\n ${MBED_PRINTF_LIB_TYPES}"
+        )
+    endif()
+    
+    mbed_set_cpu_core_definitions(mbed-core)
+    if(${MBED_TOOLCHAIN_FILE_USED})
+        message(STATUS ${MBED_TOOLCHAIN})
+        mbed_set_profile_options(mbed-core ${MBED_TOOLCHAIN})
+        mbed_set_c_lib(mbed-core ${MBED_C_LIB})
+        mbed_set_printf_lib(mbed-core ${MBED_PRINTF_LIB})
+    
+        target_compile_features(mbed-core
+            INTERFACE
+                c_std_11
+                cxx_std_14
+        )
+    
+    endif()
 
-mbed_set_cpu_core_definitions(mbed-core)
-if(${MBED_TOOLCHAIN_FILE_USED})
-    mbed_set_profile_options(mbed-core ${MBED_TOOLCHAIN})
-    mbed_set_c_lib(mbed-core ${MBED_C_LIB})
-    mbed_set_printf_lib(mbed-core ${MBED_PRINTF_LIB})
-
-    target_compile_features(mbed-core
-        INTERFACE
-            c_std_11
-            cxx_std_14
-    )
-
-endif()
-
-target_compile_definitions(mbed-core
-    INTERFACE
-        ${MBED_TARGET_DEFINITIONS}
-        ${MBED_CONFIG_DEFINITIONS}
-)
-
-# Add MBED_TEST_MODE for backward compatibility with Greentea tests written for use with Mbed CLI 1
-if(CMAKE_PROJECT_NAME STREQUAL PROJECT_NAME AND BUILD_TESTING)
-    target_compile_definitions(${PROJECT_NAME}
-        PUBLIC
-            MBED_TEST_MODE
-    )
-endif()
-
-# We need to generate a "response file" to pass to the C preprocessor when we preprocess the linker
-# script, because of path length limitations on Windows. We set the response file and bind the path
-# to a global property here. The MBED_TARGET being built queries this global property when it sets
-# the linker script.
-#
-# We must set this global property before the targets subdirectory is added to the project. This is
-# required because the MBED_TARGET depends on the response file. If the path to the response file
-# is not defined when the target requests it the config definitions will not be passed to CPP.
-#
-# TODO: Remove this and find a more idiomatic way of passing compile definitions to CPP without
-# using response files or global properties.
-mbed_generate_options_for_linker(mbed-core RESPONSE_FILE_PATH)
-set_property(GLOBAL PROPERTY COMPILE_DEFS_RESPONSE_FILE ${RESPONSE_FILE_PATH})
-
-# Add compile definitions for backward compatibility with the toolchain
-# supported. New source files should instead check for __GNUC__ and __clang__
-# for the GCC_ARM and ARM toolchains respectively.
-if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
     target_compile_definitions(mbed-core
         INTERFACE
-            TOOLCHAIN_GCC_ARM
-            TOOLCHAIN_GCC
+            ${MBED_TARGET_DEFINITIONS}
+            ${MBED_CONFIG_DEFINITIONS}
     )
-elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
-    target_compile_definitions(mbed-core
-        INTERFACE
-            TOOLCHAIN_ARM
-    )
+
+    # We need to generate a "response file" to pass to the C preprocessor when we preprocess the linker
+    # script, because of path le    ngth limitations on Windows. We set the response file and bind the path
+    # to a global property here. The MBED_TARGET being built queries this global property when it sets
+    # the linker script.
+    #
+    # We must set this global property before the targets subdirectory is added to the project. This is
+    # required because the MBED_TARGET depends on the response file. If the path to the response file
+    # is not defined when the target requests it the config definitions will not be passed to CPP.
+    #
+    # TODO: Remove this and find a more idiomatic way of passing compile definitions to CPP without
+    # using response files or global properties.
+    mbed_generate_options_for_linker(mbed-core RESPONSE_FILE_PATH)
+    set_property(GLOBAL PROPERTY COMPILE_DEFS_RESPONSE_FILE ${RESPONSE_FILE_PATH})
+    
+    # Add compile definitions for backward compatibility with the toolchain
+    # supported. New source files should instead check for __GNUC__ and __clang__
+    # for the GCC_ARM and ARM toolchains respectively.
+    if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+        target_compile_definitions(mbed-core
+            INTERFACE
+                TOOLCHAIN_GCC_ARM
+                TOOLCHAIN_GCC
+        )
+    elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
+        target_compile_definitions(mbed-core
+            INTERFACE
+                TOOLCHAIN_ARM
+        )
+    endif()
 endif()
 
 # Include mbed.h and config from generate folder
@@ -135,24 +144,35 @@
 add_subdirectory(hal)
 add_subdirectory(platform)
 add_subdirectory(rtos)
-add_subdirectory(targets)
+
+if(${CMAKE_CROSSCOMPILING})
+    add_subdirectory(targets)
+    # The directories below contain optional target libraries
+    add_subdirectory(connectivity EXCLUDE_FROM_ALL)
+    add_subdirectory(storage EXCLUDE_FROM_ALL)
+    add_subdirectory(events EXCLUDE_FROM_ALL)
+else()
+    add_subdirectory(connectivity)
+    add_subdirectory(storage)
+    add_subdirectory(events)
+endif()
 
 # The directories below contain optional target libraries
-add_subdirectory(events EXCLUDE_FROM_ALL)
-add_subdirectory(connectivity EXCLUDE_FROM_ALL)
-add_subdirectory(storage EXCLUDE_FROM_ALL)
 add_subdirectory(drivers/device_key EXCLUDE_FROM_ALL)
 add_subdirectory(drivers/usb EXCLUDE_FROM_ALL)
 add_subdirectory(features EXCLUDE_FROM_ALL)
 add_subdirectory(cmsis/CMSIS_5/CMSIS/RTOS2 EXCLUDE_FROM_ALL)
 add_subdirectory(cmsis/device/rtos EXCLUDE_FROM_ALL)
 
-# Ensure the words that make up the Mbed target name are separated with a hyphen, lowercase, and with the `mbed-` prefix.
-string(TOLOWER ${MBED_TARGET} MBED_TARGET_CONVERTED)
-string(REPLACE "_" "-" MBED_TARGET_CONVERTED ${MBED_TARGET_CONVERTED})
-string(PREPEND MBED_TARGET_CONVERTED "mbed-")
 
-target_link_libraries(mbed-core INTERFACE ${MBED_TARGET_CONVERTED})
+if(${CMAKE_CROSSCOMPILING})
+    # Ensure the words that make up the Mbed target name are separated with a hyphen, lowercase, and with the `mbed-` prefix.
+    string(TOLOWER ${MBED_TARGET} MBED_TARGET_CONVERTED)
+    string(REPLACE "_" "-" MBED_TARGET_CONVERTED ${MBED_TARGET_CONVERTED})
+    string(PREPEND MBED_TARGET_CONVERTED "mbed-")
+    
+    target_link_libraries(mbed-core INTERFACE ${MBED_TARGET_CONVERTED})
+endif()
 
 #
 # Converts output file of `target` to binary file and to Intel HEX file.
diff --git a/UNITTESTS/CMakeLists.txt b/UNITTESTS/CMakeLists.txt
index 6aba4ba..bb00da9 100644
--- a/UNITTESTS/CMakeLists.txt
+++ b/UNITTESTS/CMakeLists.txt
@@ -1,75 +1,39 @@
-cmake_minimum_required(VERSION 3.0.2)
-
-set(PROJECT_NAME unittests)
-set(LIB_NAME MbedOS)
-
-project(${PROJECT_NAME})
+# Copyright (c) 2021 ARM Limited. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
 
 # Setup c++ standard
-macro(use_cxx14)
-    if (CMAKE_VERSION VERSION_LESS 3.1)
-        if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-            set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++14")
-        endif()
-    else()
-        set(CMAKE_CXX_STANDARD 14)
-        set(CMAKE_CXX_STANDARD_REQUIRED ON)
-    endif()
-endmacro()
+set(CMAKE_CXX_STANDARD 14 CACHE STRING "")
+set(CMAKE_CXX_STANDARD_REQUIRED ON CACHE BOOL "")
 
-use_cxx14()
-
+add_definitions(-DUNITTEST)
 
 if (MINGW)
-  # enable PRIx formatting globally
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -D__STDC_FORMAT_MACROS")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -D__STDC_FORMAT_MACROS")
+    # enable PRIx formatting globally
+    add_definitions(-D__STDC_FORMAT_MACROS)
 endif (MINGW)
 
 ####################
 # GTEST
 ####################
-
-# Download and unpack googletest at configure time
-configure_file(googletest-CMakeLists.txt.in googletest-download/CMakeLists.txt)
-execute_process(COMMAND ${CMAKE_COMMAND} -G "${CMAKE_GENERATOR}" .
-    RESULT_VARIABLE result
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download)
-if (result)
-    message(FATAL_ERROR "CMake failed for google test: ${result}")
-endif()
-execute_process(COMMAND ${CMAKE_COMMAND} --build .
-    RESULT_VARIABLE result
-    WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download)
-if (result)
-    message(FATAL_ERROR "Build failed for google test: ${result}")
-endif()
+include(FetchContent)
+# Download and unpack googletest
+FetchContent_Declare(googletest
+    GIT_REPOSITORY https://github.com/google/googletest.git
+    GIT_TAG release-1.10.0
+)
+FetchContent_MakeAvailable(googletest)
 
 # Prevent overriding the parent project's compiler/linker
 # settings on Windows
 set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
 
-# Add googletest directly to our build. This defines
-# the gtest and gtest_main targets.
-add_subdirectory(${CMAKE_BINARY_DIR}/googletest-src
-                 ${CMAKE_BINARY_DIR}/googletest-build
-                 EXCLUDE_FROM_ALL)
-
-# The gtest/gtest_main/gmock/gmock_main targets carry header search path
-# dependencies automatically when using CMake 2.8.11 or
-# later.
-target_include_directories(gmock_main SYSTEM BEFORE INTERFACE
-  "$<BUILD_INTERFACE:${gtest_SOURCE_DIR}/include>"
-  "$<BUILD_INTERFACE:${gmock_SOURCE_DIR}/include>")
 
 ####################
 # TESTING
 ####################
 
-include(CTest)
-
 set_property(DIRECTORY APPEND PROPERTY ADDITIONAL_MAKE_CLEAN_FILES
-  "${CMAKE_BINARY_DIR}/Testing"
+    "${CMAKE_BINARY_DIR}/Testing"
 )
 
 ####################
@@ -78,163 +42,19 @@
 
 if (COVERAGE)
 
-  if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
-    message(WARNING "Non-debug build may result misleading code coverage results.")
-  endif()
+    if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
+        message(WARNING "Non-debug build may result misleading code coverage results.")
+    endif()
 
-  # Append coverage compiler flags
-  set(COVERAGE_COMPILER_FLAGS "-g -O0 --coverage")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${COVERAGE_COMPILER_FLAGS}")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COVERAGE_COMPILER_FLAGS}")
+    # Append coverage compiler flags
+    set(COVERAGE_COMPILER_FLAGS "-g -O0 --coverage")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${COVERAGE_COMPILER_FLAGS}" CACHE STRING "" FORCE)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${COVERAGE_COMPILER_FLAGS}" CACHE STRING "" FORCE)
 
 endif(COVERAGE)
 
 if (VALGRIND)
-  find_program(MEMORYCHECK_COMMAND valgrind)
+    find_program(MEMORYCHECK_COMMAND valgrind)
 endif(VALGRIND)
 
-####################
-# UNIT TESTS
-####################
-
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -DUNITTEST")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -DUNITTEST")
-
-# Set include dirs.
-set(unittest-includes-base
-  "${PROJECT_SOURCE_DIR}/target_h"
-  "${PROJECT_SOURCE_DIR}/../events/tests/UNITTESTS/target_h"
-  "${PROJECT_SOURCE_DIR}/../events/tests/UNITTESTS/target_h/equeue"
-  "${PROJECT_SOURCE_DIR}/target_h/platform"
-  "${PROJECT_SOURCE_DIR}/target_h/platform/cxxsupport"
-  "${PROJECT_SOURCE_DIR}/target_h/drivers"
-  "${PROJECT_SOURCE_DIR}/target_h/rtos/include"
-  "${PROJECT_SOURCE_DIR}/stubs"
-  "${PROJECT_SOURCE_DIR}/.."
-  "${PROJECT_SOURCE_DIR}/../features"
-  "${PROJECT_SOURCE_DIR}/../platform/include"
-  "${PROJECT_SOURCE_DIR}/../platform/include/platform"
-  "${PROJECT_SOURCE_DIR}/../platform/mbed-trace/include"
-  "${PROJECT_SOURCE_DIR}/../storage/filesystem/littlefs/include"
-  "${PROJECT_SOURCE_DIR}/../storage/filesystem/fat/include"
-  "${PROJECT_SOURCE_DIR}/../storage/blockdevice/include"
-  "${PROJECT_SOURCE_DIR}/../storage/filesystem/include"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/include"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/kv_config"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/kv_config/include"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/tdbstore/include"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/filesystemstore/include"
-  "${PROJECT_SOURCE_DIR}/../storage/kvstore/kvstore_global_api/include"
-  "${PROJECT_SOURCE_DIR}/../drivers"
-  "${PROJECT_SOURCE_DIR}/../drivers/include"
-  "${PROJECT_SOURCE_DIR}/../drivers/include/drivers"
-  "${PROJECT_SOURCE_DIR}/../drivers/include/drivers/internal"
-  "${PROJECT_SOURCE_DIR}/../hal"
-  "${PROJECT_SOURCE_DIR}/../hal/include"
-  "${PROJECT_SOURCE_DIR}/../events/include"
-  "${PROJECT_SOURCE_DIR}/../events/include/events/internal"
-  "${PROJECT_SOURCE_DIR}/../events/source"
-  "${PROJECT_SOURCE_DIR}/../rtos/include"
-  "${PROJECT_SOURCE_DIR}/../features/frameworks"
-  "${PROJECT_SOURCE_DIR}/../connectivity/libraries/nanostack-libservice"
-  "${PROJECT_SOURCE_DIR}/../connectivity/libraries/nanostack-libservice/mbed-client-libservice"
-  "${PROJECT_SOURCE_DIR}/../connectivity/netsocket/include"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/fat"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/fat/ChaN"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/bd"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/littlefs"
-  "${PROJECT_SOURCE_DIR}/../features/filesystem/littlefs/littlefs"
-  "${PROJECT_SOURCE_DIR}/../connectivity/cellular/include/cellular/framework/API"
-  "${PROJECT_SOURCE_DIR}/../connectivity/cellular/include/cellular/framework/AT"
-  "${PROJECT_SOURCE_DIR}/../connectivity/cellular/include/cellular/framework/device"
-  "${PROJECT_SOURCE_DIR}/../connectivity/cellular/include/cellular/framework"
-  "${PROJECT_SOURCE_DIR}/../connectivity/cellular/include/cellular/framework/common"
-  "${PROJECT_SOURCE_DIR}/../connectivity"
-  "${PROJECT_SOURCE_DIR}/../connectivity/lorawan/include/lorawan"
-  "${PROJECT_SOURCE_DIR}/../connectivity/lorawan/lorastack"
-  "${PROJECT_SOURCE_DIR}/../connectivity/lorawan/lorastack/mac"
-  "${PROJECT_SOURCE_DIR}/../connectivity/lorawan/lorastack/phy"
-  "${PROJECT_SOURCE_DIR}/../connectivity/lorawan"
-  "${PROJECT_SOURCE_DIR}/../connectivity/mbedtls"
-  "${PROJECT_SOURCE_DIR}/../connectivity/mbedtls/include"
-)
-
-# Create a list for test suites.
-set(TEST_SUITES)
-
-# Get all matched tests.
-file(GLOB_RECURSE unittest-file-list
-  "../unittest.cmake" # matches any ../**/unittest.cmake
-)
-
-if ("${unittest-file-list}" STREQUAL "")
-  message(FATAL_ERROR "No tests found. Exiting...")
-endif()
-
-# Create unit test targets
-foreach(testfile ${unittest-file-list})
-  ####################
-  # DEFINE TARGETS
-  ####################
-
-  # Init file lists.
-  set(unittest-includes ${unittest-includes-base})
-  set(unittest-sources)
-  set(unittest-test-sources)
-  set(unittest-test-flags)
-
-  # Get source files
-  include("${testfile}")
-
-  get_filename_component(TEST_SUITE_DIR ${testfile} DIRECTORY)
-
-  file(RELATIVE_PATH
-       TEST_SUITE_NAME # output
-       "${PROJECT_SOURCE_DIR}/.." # root
-       ${TEST_SUITE_DIR} #abs dirpath
-  )
-
-  string(REGEX REPLACE "/|\\\\" "-" TEST_SUITE_NAME ${TEST_SUITE_NAME})
-
-  set(TEST_SUITES ${TEST_SUITES} ${TEST_SUITE_NAME})
-
-  set(LIBS_TO_BE_LINKED gmock_main)
-
-  # Build directories list
-  set(BUILD_DIRECTORIES)
-
-  if (unittest-sources)
-    # Create the testable static library.
-    add_library("${TEST_SUITE_NAME}.${LIB_NAME}" STATIC ${unittest-sources})
-    target_include_directories("${TEST_SUITE_NAME}.${LIB_NAME}" PRIVATE
-      ${unittest-includes})
-    target_compile_options("${TEST_SUITE_NAME}.${LIB_NAME}" PRIVATE
-      ${unittest-test-flags})
-    set(LIBS_TO_BE_LINKED ${LIBS_TO_BE_LINKED} "${TEST_SUITE_NAME}.${LIB_NAME}")
-
-    # Append lib build directory to list
-    list(APPEND BUILD_DIRECTORIES "./CMakeFiles/${TEST_SUITE_NAME}.${LIB_NAME}.dir")
-  endif(unittest-sources)
-
-  if (unittest-test-sources)
-    # Create the executable.
-    add_executable(${TEST_SUITE_NAME} ${unittest-test-sources})
-
-    target_include_directories(${TEST_SUITE_NAME} PRIVATE
-      ${unittest-includes})
-    target_compile_options(${TEST_SUITE_NAME} PRIVATE
-      ${unittest-test-flags})
-
-    # Link the executable with the libraries.
-    target_link_libraries(${TEST_SUITE_NAME} ${LIBS_TO_BE_LINKED})
-
-    add_test(NAME "${TEST_SUITE_NAME}" COMMAND ${TEST_SUITE_NAME})
-
-    # Append test build directory to list
-    list(APPEND BUILD_DIRECTORIES "./CMakeFiles/${TEST_SUITE_NAME}.dir")
-  else()
-    message(WARNING "No test source files found for ${TEST_SUITE_NAME}.\n")
-  endif(unittest-test-sources)
-endforeach(testfile)
-
+add_subdirectory(stubs)
diff --git a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
index e742f14..3695d5b 100644
--- a/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
+++ b/cmsis/CMSIS_5/CMSIS/RTOS2/RTX/CMakeLists.txt
@@ -1,47 +1,49 @@
 # Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-function(_mbed_get_cortex_m_exception_handlers toolchain_dir)
-    foreach(key ${MBED_TARGET_LABELS})
-        if(${key} STREQUAL CORTEX_A)
-            set(STARTUP_RTX_FILE TARGET_CORTEX_A/irq_ca.S)
-        elseif(${key} STREQUAL M0)
-            set(STARTUP_RTX_FILE TARGET_M0/irq_cm0.S)
-        elseif(${key} STREQUAL M0P)
-            set(STARTUP_RTX_FILE TARGET_M0P/irq_cm0.S)
-        elseif(${key} STREQUAL M23)
-            set(STARTUP_RTX_FILE TARGET_M23/irq_armv8mbl.S)
-        elseif(${key} STREQUAL M3)
-            set(STARTUP_RTX_FILE TARGET_M3/irq_cm3.S)
-        elseif(${key} STREQUAL M33)
-            set(STARTUP_RTX_FILE TARGET_M33/irq_armv8mml.S)
-        elseif(${key} STREQUAL M55)
-            set(STARTUP_RTX_FILE TARGET_M33/irq_armv8mml.S)
-        elseif(${key} STREQUAL RTOS_M4_M7)
-            set(STARTUP_RTX_FILE TARGET_RTOS_M4_M7/irq_cm4f.S)
-        endif()
+if(${CMAKE_CROSSCOMPILING})
+    function(_mbed_get_cortex_m_exception_handlers toolchain_dir)
+        foreach(key ${MBED_TARGET_LABELS})
+            if(${key} STREQUAL CORTEX_A)
+                set(STARTUP_RTX_FILE TARGET_CORTEX_A/irq_ca.S)
+            elseif(${key} STREQUAL M0)
+                set(STARTUP_RTX_FILE TARGET_M0/irq_cm0.S)
+            elseif(${key} STREQUAL M0P)
+                set(STARTUP_RTX_FILE TARGET_M0P/irq_cm0.S)
+            elseif(${key} STREQUAL M23)
+                set(STARTUP_RTX_FILE TARGET_M23/irq_armv8mbl.S)
+            elseif(${key} STREQUAL M3)
+                set(STARTUP_RTX_FILE TARGET_M3/irq_cm3.S)
+            elseif(${key} STREQUAL M33)
+                set(STARTUP_RTX_FILE TARGET_M33/irq_armv8mml.S)
+            elseif(${key} STREQUAL M55)
+                set(STARTUP_RTX_FILE TARGET_M33/irq_armv8mml.S)
+            elseif(${key} STREQUAL RTOS_M4_M7)
+                set(STARTUP_RTX_FILE TARGET_RTOS_M4_M7/irq_cm4f.S)
+            endif()
 
-        target_sources(mbed-rtos
-            INTERFACE
-                Source/${toolchain_dir}/${STARTUP_RTX_FILE}
-        )
-    endforeach()
-endfunction()
-
-function(_mbed_get_cortex_a_exception_handlers)
-    foreach(key ${MBED_TARGET_LABELS})
-        if(${key} STREQUAL CORTEX_A)
-            target_sources(mbed-rtos INTERFACE Config/TARGET_CORTEX_A/handlers.c)
-        endif()
-    endforeach()
-endfunction()
-
-_mbed_get_cortex_a_exception_handlers()
-
-if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-    _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_GCC)
-elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
-    _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_ARM)
+            target_sources(mbed-rtos
+                INTERFACE
+                    Source/${toolchain_dir}/${STARTUP_RTX_FILE}
+            )
+        endforeach()
+    endfunction()
+    
+    function(_mbed_get_cortex_a_exception_handlers)
+        foreach(key ${MBED_TARGET_LABELS})
+            if(${key} STREQUAL CORTEX_A)
+                target_sources(mbed-rtos INTERFACE Config/TARGET_CORTEX_A/handlers.c)
+            endif()
+        endforeach()
+    endfunction()
+    
+    _mbed_get_cortex_a_exception_handlers()
+    
+    if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+        _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_GCC)
+    elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
+        _mbed_get_cortex_m_exception_handlers(TOOLCHAIN_ARM)
+    endif()
 endif()
 
 target_include_directories(mbed-rtos
diff --git a/cmsis/device/rtos/CMakeLists.txt b/cmsis/device/rtos/CMakeLists.txt
index 024cf56..34cd162 100644
--- a/cmsis/device/rtos/CMakeLists.txt
+++ b/cmsis/device/rtos/CMakeLists.txt
@@ -1,16 +1,18 @@
 # Copyright (c) 2020-2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
-if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-    target_sources(mbed-rtos
-        INTERFACE
-            TOOLCHAIN_GCC_ARM/mbed_boot_gcc_arm.c
-    )
-elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
-    target_sources(mbed-rtos
-        INTERFACE
-            TOOLCHAIN_ARM_STD/mbed_boot_arm_std.c
-    )
+if(${CMAKE_CROSSCOMPILING})
+    if(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+        target_sources(mbed-rtos
+            INTERFACE
+                TOOLCHAIN_GCC_ARM/mbed_boot_gcc_arm.c
+        )
+    elseif(${MBED_TOOLCHAIN} STREQUAL "ARM")
+        target_sources(mbed-rtos
+            INTERFACE
+                TOOLCHAIN_ARM_STD/mbed_boot_arm_std.c
+        )
+    endif()
 endif()
 
 target_include_directories(mbed-rtos
diff --git a/connectivity/drivers/wifi/TARGET_WICED/CMakeLists.txt b/connectivity/drivers/wifi/TARGET_WICED/CMakeLists.txt
index c6f83e6..8bcf367 100644
--- a/connectivity/drivers/wifi/TARGET_WICED/CMakeLists.txt
+++ b/connectivity/drivers/wifi/TARGET_WICED/CMakeLists.txt
@@ -3,13 +3,15 @@
 
 add_library(mbed-wiced INTERFACE)
 
-if(${MBED_TOOLCHAIN} STREQUAL "ARM")
-    set(LIB_WICED_DRIVERS TOOLCHAIN_ARMC6/TARGET_WIO_EMW3166/libwiced_drivers.ar)
-elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
-    set(LIB_WICED_DRIVERS TOOLCHAIN_GCC_ARM/TARGET_WIO_EMW3166/libwiced_drivers.a)
-endif()
+if(${CMAKE_CROSSCOMPILING})
+    if(${MBED_TOOLCHAIN} STREQUAL "ARM")
+        set(LIB_WICED_DRIVERS TOOLCHAIN_ARMC6/TARGET_WIO_EMW3166/libwiced_drivers.ar)
+    elseif(${MBED_TOOLCHAIN} STREQUAL "GCC_ARM")
+        set(LIB_WICED_DRIVERS TOOLCHAIN_GCC_ARM/TARGET_WIO_EMW3166/libwiced_drivers.a)
+    endif()
 
 target_link_libraries(mbed-wiced INTERFACE ${CMAKE_CURRENT_SOURCE_DIR}/${LIB_WICED_DRIVERS})
+endif()
 
 target_include_directories(mbed-wiced
     INTERFACE