diff --git a/rtos/rtx/TARGET_CORTEX_A/RTX_Conf_CA.c b/rtos/rtx/TARGET_CORTEX_A/RTX_Conf_CA.c
index 6e500e8b8a..97b64a5ec5 100644
--- a/rtos/rtx/TARGET_CORTEX_A/RTX_Conf_CA.c
+++ b/rtos/rtx/TARGET_CORTEX_A/RTX_Conf_CA.c
@@ -107,7 +107,11 @@
 //   <i> Initialize thread stack with watermark pattern for analyzing stack usage (current/maximum) in System and Thread Viewer.
 //   <i> Enabling this option increases significantly the execution time of osThreadCreate.
 #ifndef OS_STKINIT
-#define OS_STKINIT      0
+  #if (defined(MBED_STACK_STATS_ENABLED) && MBED_STACK_STATS_ENABLED)
+   #define OS_STKINIT   1
+  #else
+   #define OS_STKINIT   0
+  #endif
 #endif
 
 //   <o>Processor mode for thread execution
diff --git a/rtos/rtx/TARGET_CORTEX_A/rt_CMSIS.c b/rtos/rtx/TARGET_CORTEX_A/rt_CMSIS.c
index e629c1d089..82c7619dd8 100644
--- a/rtos/rtx/TARGET_CORTEX_A/rt_CMSIS.c
+++ b/rtos/rtx/TARGET_CORTEX_A/rt_CMSIS.c
@@ -843,10 +843,27 @@ os_InRegs osEvent_type svcThreadGetInfo (osThreadId thread_id, osThreadInfo info
   }
 
   if (osThreadInfoStackMax == info) {
-    // Cortex-A RTX does not have stack init so
-    // the maximum stack usage cannot be obtained.
-    ret.status = osErrorResource;
-    return osEvent_ret_status;
+    uint32_t i;
+    uint32_t *stack_ptr;
+    uint32_t stack_size;
+    if (!(os_stackinfo & (1 << 28))) {
+      // Stack init must be turned on for max stack usage
+      ret.status = osErrorResource;
+      return osEvent_ret_status;
+    }
+    stack_ptr = (uint32_t*)ptcb->stack;
+    stack_size = ptcb->priv_stack;
+    if (0 == stack_size) {
+      // This is an OS task - always a fixed size
+      stack_size = os_stackinfo & 0x3FFFF;
+    }
+    for (i = 1; i <stack_size / 4; i++) {
+      if (stack_ptr[i] != MAGIC_PATTERN) {
+        break;
+      }
+    }
+    ret.value.v = stack_size - i * 4;
+    return osEvent_ret_value;
   }
 
   if (osThreadInfoEntry == info) {