diff --git a/testhal/STM32F4xx/ADC/Makefile b/testhal/STM32F4xx/ADC/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/ADC/Makefile
+++ b/testhal/STM32F4xx/ADC/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/EXT/Makefile b/testhal/STM32F4xx/EXT/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/EXT/Makefile
+++ b/testhal/STM32F4xx/EXT/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/GPT/Makefile b/testhal/STM32F4xx/GPT/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/GPT/Makefile
+++ b/testhal/STM32F4xx/GPT/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/IRQ_STORM/Makefile b/testhal/STM32F4xx/IRQ_STORM/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/IRQ_STORM/Makefile
+++ b/testhal/STM32F4xx/IRQ_STORM/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile b/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
index 1ea497fbc..0bdb34ed3 100644
--- a/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
+++ b/testhal/STM32F4xx/IRQ_STORM_FPU/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/IRQ_STORM_FPU/main.c b/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
index 0809b624a..47194e090 100644
--- a/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
+++ b/testhal/STM32F4xx/IRQ_STORM_FPU/main.c
@@ -75,18 +75,19 @@ static msg_t WorkerThread(void *arg) {
  * GPT2 callback.
  */
 static void gpt2cb(GPTDriver *gptp) {
-  float f1, f2, f3, f4, f5;
+/*  float f1, f2, f3, f4, f5;*/
 
   (void)gptp;
 
-  f1 = ff1(2);
+/*  f1 = ff1(2);
   f2 = ff1(3);
   f3 = ff1(4);
   f5 = f1 + f2 + f3;
   f4 = ff1(5);
   f5 = ff2(f5, f4, f5, f4);
   if (f5 != 196)
-    chSysHalt();
+    chSysHalt();*/
+  volatile float f1 = ff1(67);
 }
 
 /*
diff --git a/testhal/STM32F4xx/PWM-ICU/Makefile b/testhal/STM32F4xx/PWM-ICU/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/PWM-ICU/Makefile
+++ b/testhal/STM32F4xx/PWM-ICU/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/SPI/Makefile b/testhal/STM32F4xx/SPI/Makefile
index 7318496d3..dfc4ac9f0 100644
--- a/testhal/STM32F4xx/SPI/Makefile
+++ b/testhal/STM32F4xx/SPI/Makefile
@@ -120,7 +120,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-
diff --git a/testhal/STM32F4xx/UART/Makefile b/testhal/STM32F4xx/UART/Makefile
index c2f0abcd4..f392d9733 100644
--- a/testhal/STM32F4xx/UART/Makefile
+++ b/testhal/STM32F4xx/UART/Makefile
@@ -118,7 +118,7 @@ INCDIR = $(PORTINC) $(KERNINC) $(TESTINC) \
 # Compiler settings
 #
 
-MCU  = cortex-m3
+MCU  = cortex-m4
 
 #TRGT = arm-elf-
 TRGT = arm-none-eabi-