diff --git a/miosix/config/Makefile.inc b/miosix/config/Makefile.inc
index 394524705b86158e44fa33aa08d40db844a87f11..f031af986f209daa1ee6c9609c789a4166f4a2e0 100644
--- a/miosix/config/Makefile.inc
+++ b/miosix/config/Makefile.inc
@@ -17,7 +17,7 @@
 #OPT_BOARD := stm32f100rb_stm32vldiscovery
 #OPT_BOARD := stm32f103ve_strive_mini
 #OPT_BOARD := stm32f103ze_redbull_v2
-OPT_BOARD := stm32f407vg_stm32f4discovery
+#OPT_BOARD := stm32f407vg_stm32f4discovery
 #OPT_BOARD := stm32f207ig_stm3220g-eval
 #OPT_BOARD := stm32f207zg_ethboard_v2
 #OPT_BOARD := stm32f207ze_als_camboard
@@ -58,8 +58,8 @@ OPT_BOARD := stm32f407vg_stm32f4discovery
 ## -O2 is recomended otherwise, as it provides a good balance between code
 ## size and speed
 ##
-OPT_OPTIMIZATION := -O0
-#OPT_OPTIMIZATION := -O2
+#OPT_OPTIMIZATION := -O0
+OPT_OPTIMIZATION := -O2
 #OPT_OPTIMIZATION := -O3
 #OPT_OPTIMIZATION := -Os
 
diff --git a/miosix/config/miosix_settings.h b/miosix/config/miosix_settings.h
index dcb9b886bb56d6f08532cef85967e04bc9593510..417bc18e33f0ab40797c743b88cf424b149be147 100644
--- a/miosix/config/miosix_settings.h
+++ b/miosix/config/miosix_settings.h
@@ -149,7 +149,7 @@ const unsigned char MAX_OPEN_FILES=8;
  * mode, so to use debugging it is necessary to disable sleep in the idle thread.
  * By default it is not defined (idle thread calls sleep).
  */
-#define JTAG_DISABLE_SLEEP
+//#define JTAG_DISABLE_SLEEP
 
 /// Minimum stack size (MUST be divisible by 4)
 const unsigned int STACK_MIN=256;