diff --git a/events/equeue/equeue_platform.h b/events/equeue/equeue_platform.h
index 5a16e07..9c5bec2 100644
--- a/events/equeue/equeue_platform.h
+++ b/events/equeue/equeue_platform.h
@@ -51,7 +51,7 @@
 #include <pthread.h>
 #elif defined(EQUEUE_PLATFORM_MBED)
 #include "cmsis_os2.h"
-#include "rtx_lib.h"
+#include "mbed_rtos_storage.h"
 #endif
 
 
@@ -117,7 +117,7 @@
 #elif defined(EQUEUE_PLATFORM_MBED) && defined(MBED_CONF_RTOS_PRESENT)
 typedef struct equeue_sema {
     osEventFlagsId_t id;
-    os_event_flags_t mem;
+    mbed_rtos_storage_event_flags_t mem;
 } equeue_sema_t;
 #elif defined(EQUEUE_PLATFORM_MBED)
 typedef volatile int equeue_sema_t;
diff --git a/rtos/Mail.h b/rtos/Mail.h
index b4a0289..602907e 100644
--- a/rtos/Mail.h
+++ b/rtos/Mail.h
@@ -28,7 +28,7 @@
 #include "Queue.h"
 #include "MemoryPool.h"
 #include "cmsis_os2.h"
-#include "rtx_lib.h"
+#include "mbed_rtos_storage.h"
 #include "mbed_rtos1_types.h"
 
 #include "platform/NonCopyable.h"
diff --git a/rtos/RtosTimer.h b/rtos/RtosTimer.h
index b490fd3..3abef47 100644
--- a/rtos/RtosTimer.h
+++ b/rtos/RtosTimer.h
@@ -24,7 +24,7 @@
 
 #include <stdint.h>
 #include "cmsis_os2.h"
-#include "rtx_lib.h"
+#include "mbed_rtos_storage.h"
 #include "platform/Callback.h"
 #include "platform/NonCopyable.h"
 #include "platform/mbed_toolchain.h"
@@ -150,7 +150,7 @@
 
     osTimerId_t _id;
     osTimerAttr_t _attr;
-    os_timer_t _obj_mem;
+    mbed_rtos_storage_timer_t _obj_mem;
     mbed::Callback<void()> _function;
 };
 
diff --git a/rtos/TARGET_CORTEX/mbed_rtos_storage.h b/rtos/TARGET_CORTEX/mbed_rtos_storage.h
index 50e9227..11ebc43 100644
--- a/rtos/TARGET_CORTEX/mbed_rtos_storage.h
+++ b/rtos/TARGET_CORTEX/mbed_rtos_storage.h
@@ -41,6 +41,7 @@
  */
 
 #include "rtx_lib.h"
+#include "mbed_rtx_conf.h"
 
 typedef os_mutex_t mbed_rtos_storage_mutex_t;
 typedef os_semaphore_t mbed_rtos_storage_semaphore_t;
diff --git a/rtos/TARGET_CORTEX/mbed_rtx_conf.h b/rtos/TARGET_CORTEX/mbed_rtx_conf.h
index b4fe1d4..304c2a1 100644
--- a/rtos/TARGET_CORTEX/mbed_rtx_conf.h
+++ b/rtos/TARGET_CORTEX/mbed_rtx_conf.h
@@ -24,6 +24,9 @@
 
 #include "mbed_rtx.h"
 
+/** Any access to RTX5 specific data structures used in common code should be wrapped in ifdef MBED_OS_BACKEND_RTX5 */
+#define MBED_OS_BACKEND_RTX5
+
 /** The thread's stack size can be configured by the application, if not explicitly specified it'll default to 4K */
 #ifndef MBED_CONF_APP_THREAD_STACK_SIZE
 #define MBED_CONF_APP_THREAD_STACK_SIZE 4096
diff --git a/rtos/Thread.cpp b/rtos/Thread.cpp
index 2db5ecc..f01f1b1 100644
--- a/rtos/Thread.cpp
+++ b/rtos/Thread.cpp
@@ -168,7 +168,11 @@
     _mutex.lock();
 
     if (_tid != NULL) {
+#if defined(MBED_OS_BACKEND_RTX5)
         state = _obj_mem.state;
+#else
+        state = osThreadGetState(_tid);
+#endif
     }
 
     _mutex.unlock();
@@ -185,6 +189,7 @@
         case osThreadRunning:
             user_state = Running;
             break;
+#if defined(MBED_OS_BACKEND_RTX5)
         case osRtxThreadWaitingDelay:
             user_state = WaitingDelay;
             break;
@@ -212,6 +217,7 @@
         case osRtxThreadWaitingMessagePut:
             user_state = WaitingMessagePut;
             break;
+#endif
         case osThreadTerminated:
         default:
             user_state = Deleted;
@@ -226,8 +232,7 @@
     _mutex.lock();
 
     if (_tid != NULL) {
-        os_thread_t *thread = (os_thread_t *)_tid;
-        size = thread->stack_size;
+        size = osThreadGetStackSize(_tid);
     }
 
     _mutex.unlock();
@@ -238,10 +243,12 @@
     uint32_t size = 0;
     _mutex.lock();
 
+#if defined(MBED_OS_BACKEND_RTX5)
     if (_tid != NULL) {
         os_thread_t *thread = (os_thread_t *)_tid;
         size = (uint32_t)thread->sp - (uint32_t)thread->stack_mem;
     }
+#endif
 
     _mutex.unlock();
     return size;
@@ -251,10 +258,12 @@
     uint32_t size = 0;
     _mutex.lock();
 
+#if defined(MBED_OS_BACKEND_RTX5)
     if (_tid != NULL) {
         os_thread_t *thread = (os_thread_t *)_tid;
         size = ((uint32_t)thread->stack_mem + thread->stack_size) - thread->sp;
     }
+#endif
 
     _mutex.unlock();
     return size;
@@ -265,11 +274,15 @@
     _mutex.lock();
 
     if (_tid != NULL) {
+#if defined(MBED_OS_BACKEND_RTX5)
         os_thread_t *thread = (os_thread_t *)_tid;
         uint32_t high_mark = 0;
         while (((uint32_t *)(thread->stack_mem))[high_mark] == 0xE25A2EA5)
             high_mark++;
         size = thread->stack_size - (high_mark * sizeof(uint32_t));
+#else
+        size = osThreadGetStackSize(_tid) - osThreadGetStackSpace(_tid);
+#endif
     }
 
     _mutex.unlock();
diff --git a/rtos/Thread.h b/rtos/Thread.h
index 3d921bd..7aa4faa 100644
--- a/rtos/Thread.h
+++ b/rtos/Thread.h
@@ -26,7 +26,6 @@
 #include "cmsis_os2.h"
 #include "mbed_rtos1_types.h"
 #include "mbed_rtos_storage.h"
-#include "mbed_rtx_conf.h"
 #include "platform/Callback.h"
 #include "platform/mbed_toolchain.h"
 #include "platform/NonCopyable.h"
diff --git a/rtos/rtos.h b/rtos/rtos.h
index cf81663..7a10c8e 100644
--- a/rtos/rtos.h
+++ b/rtos/rtos.h
@@ -25,8 +25,6 @@
 #ifndef RTOS_H
 #define RTOS_H
 
-#include "mbed_rtx.h"
-#include "mbed_rtx_conf.h"
 #include "mbed_rtos_storage.h"
 #include "rtos/Thread.h"
 #include "rtos/Mutex.h"