diff --git a/rtos/tests/TESTS/mbed_rtos/basic/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/basic/CMakeLists.txt
index c2bbccd..394000e 100644
--- a/rtos/tests/TESTS/mbed_rtos/basic/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/basic/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "RTOS basic test cases require RTOS with multithread to run")
 endif()
 
diff --git a/rtos/tests/TESTS/mbed_rtos/condition_variable/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/condition_variable/CMakeLists.txt
index 88b79eb..4ffb890 100644
--- a/rtos/tests/TESTS/mbed_rtos/condition_variable/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/condition_variable/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "Condition variable test cases require RTOS with multithread to run")
 endif()
 
diff --git a/rtos/tests/TESTS/mbed_rtos/heap_and_stack/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/heap_and_stack/CMakeLists.txt
index 0740eff..58d04db 100644
--- a/rtos/tests/TESTS/mbed_rtos/heap_and_stack/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/heap_and_stack/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED TARGET_CORTEX_A)
+if("TARGET_CORTEX_A" IN_LIST MBED_TARGET_DEFINITIONS)
     set(TEST_SKIPPED "test not supported for cortex-A.")
 elseif(NOT "DEVICE_USTICKER=1" IN_LIST MBED_TARGET_DEFINITIONS)
     set(TEST_SKIPPED "UsTicker need to be enabled for this test.")
diff --git a/rtos/tests/TESTS/mbed_rtos/mail/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/mail/CMakeLists.txt
index 62b2bcd..b311e2a 100644
--- a/rtos/tests/TESTS/mbed_rtos/mail/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/mail/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "mail test cases require RTOS with multithread to run")
 endif()
 
diff --git a/rtos/tests/TESTS/mbed_rtos/mutex/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/mutex/CMakeLists.txt
index 4ebc9c2..0d123c9 100644
--- a/rtos/tests/TESTS/mbed_rtos/mutex/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/mutex/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "Mutex test cases require RTOS with multithread to run")
 endif()
 
diff --git a/rtos/tests/TESTS/mbed_rtos/queue/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/queue/CMakeLists.txt
index 7bc1e97..a66628b 100644
--- a/rtos/tests/TESTS/mbed_rtos/queue/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/queue/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "Queue test cases require RTOS with multithread to run")
 endif()
 
diff --git a/rtos/tests/TESTS/mbed_rtos/threads/CMakeLists.txt b/rtos/tests/TESTS/mbed_rtos/threads/CMakeLists.txt
index d330bf2..d40b9cf 100644
--- a/rtos/tests/TESTS/mbed_rtos/threads/CMakeLists.txt
+++ b/rtos/tests/TESTS/mbed_rtos/threads/CMakeLists.txt
@@ -3,7 +3,7 @@
 
 include(mbed_greentea)
 
-if(DEFINED MBED_RTOS_SINGLE_THREAD OR MBED_GREENTEA_TEST_BAREMETAL)
+if(${MBED_C_LIB} STREQUAL "small" OR MBED_GREENTEA_TEST_BAREMETAL)
     set(TEST_SKIPPED "RTOS basic test cases require RTOS with multithread to run")
 endif()