diff --git a/docs/build_profiles.md b/docs/build_profiles.md
index 7fcce288052..a984cbe2e56 100644
--- a/docs/build_profiles.md
+++ b/docs/build_profiles.md
@@ -7,15 +7,17 @@ the the profile.
 
 ## Default profile
 * Small and fast code
-* Full error information - e.x. asserts have filename and line number
+* Full error information - e.g. asserts have filename and line number
 * Hard to follow code flow when using a debugger
 
 ## Debug profile
 * Easy to step through code with a debugger
-* Full error information - e.x. asserts have filename and line number
+* Full error information - e.g. asserts have filename and line number
 * Largest and slowest profile
 
 ## Small profile
 * Smallest profile and still fast
 * Minimal error information
-* Hard to follow code flow when using a debugger
+* Chip is put to sleep when going idle:
+  * debugger is likely to drop connection
+  * breaks the [local file system](https://developer.mbed.org/handbook/LocalFileSystem) on the [mbed interface](https://developer.mbed.org/handbook/mbed-interface) (only for few NXP boards & if used)
diff --git a/rtos/rtos_idle.c b/rtos/rtos_idle.c
index c1a35ef02c5..709e09f4390 100644
--- a/rtos/rtos_idle.c
+++ b/rtos/rtos_idle.c
@@ -21,14 +21,15 @@
  */
 
 #include "rtos/rtos_idle.h"
+#include "platform/sleep.h"
 
 static void default_idle_hook(void)
 {
     /* Sleep: ideally, we should put the chip to sleep.
-     Unfortunately, this usually requires disconnecting the interface chip (debugger).
-     This can be done, but it would break the local file system.
+       Unfortunately, this usually requires disconnecting the interface chip (debugger).
+       This can be done, but it would break the local file system.
     */
-    // sleep();
+    sleep();
 }
 static void (*idle_hook_fptr)(void) = &default_idle_hook;