diff --git a/boards/arm/stm32/stm32f4discovery/scripts/Make.defs b/boards/arm/stm32/stm32f4discovery/scripts/Make.defs
index 48179cb2a5..189670ae2d 100644
--- a/boards/arm/stm32/stm32f4discovery/scripts/Make.defs
+++ b/boards/arm/stm32/stm32f4discovery/scripts/Make.defs
@@ -55,9 +55,6 @@ else
   ARCHSCRIPT = -T$(TOPDIR)/boards/$(CONFIG_ARCH)/$(CONFIG_ARCH_CHIP)/$(CONFIG_ARCH_BOARD)/scripts/$(LDSCRIPT)
 endif
 
-CC = $(CROSSDEV)gcc
-CXX = $(CROSSDEV)g++
-CPP = $(CROSSDEV)gcc -E
 LD = $(CROSSDEV)ld
 STRIP = $(CROSSDEV)strip --strip-unneeded
 AR = $(ARCROSSDEV)ar rcs
@@ -65,7 +62,6 @@ NM = $(ARCROSSDEV)nm
 OBJCOPY = $(CROSSDEV)objcopy
 OBJDUMP = $(CROSSDEV)objdump
 
-ARCHCCVERSION = ${shell $(CC) -v 2>&1 | sed -n '/^gcc version/p' | sed -e 's/^gcc version \([0-9\.]\)/\1/g' -e 's/[-\ ].*//g' -e '1q'}
 ARCHCCMAJOR = ${shell echo $(ARCHCCVERSION) | cut -d'.' -f1}
 
 ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
@@ -73,19 +69,41 @@ ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
 endif
 
 ifneq ($(CONFIG_DEBUG_NOOPT),y)
-  ARCHOPTIMIZATION += $(MAXOPTIMIZATION) -fno-strict-aliasing -fno-strength-reduce -fomit-frame-pointer
+  ARCHOPTIMIZATION += $(MAXOPTIMIZATION) -fno-strict-aliasing -fomit-frame-pointer
 endif
 
 ARCHCFLAGS = -fno-builtin
-ARCHCXXFLAGS = -fno-builtin -fno-exceptions -fcheck-new -fno-rtti
+ARCHCXXFLAGS = -fno-builtin -fno-exceptions -fcheck-new
 ARCHWARNINGS = -Wall -Wstrict-prototypes -Wshadow -Wundef
 ARCHWARNINGSXX = -Wall -Wshadow -Wundef
 ARCHDEFINES =
 ARCHPICFLAGS = -fpic -msingle-pic-base -mpic-register=r10
 
-CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe -funwind-tables
+ifeq ($(CONFIG_ARMV7M_TOOLCHAIN_CLANGL),y)
+  ARCHCCVERSION = {shell $(CC) -v 2>&1 | sed -n '/clang version/p' | sed -e 's/.* clang version \([0-9\.]\)/\1/g' -e 's/[-\ ].*//g'}
+  HOSTCC = clang
+  CC = clang
+  CXX = clang++
+  CPP = clang -E
+  ARCHCFLAGS += -nostdlib -ffreestanding -target arm-none-eabi -march=armv7-m -mcpu=cortex-m4
+  ARCHCXXFLAGS += -nostdlib -ffreestanding -target arm-none-eabi -march=armv7-m -mcpu=cortex-m4 -DCONFIG_WCHAR_BUILTIN
+else
+  ARCHCCVERSION = ${shell $(CC) -v 2>&1 | sed -n '/^gcc version/p' | sed -e 's/^gcc version \([0-9\.]\)/\1/g' -e 's/[-\ ].*//g' -e '1q'}
+  HOSTCC = gcc
+  CC = $(CROSSDEV)gcc
+  CXX = $(CROSSDEV)g++
+  CPP = $(CROSSDEV)gcc -E
+  ARCHCFLAGS += -funwind-tables
+  ARCHCXXFLAGS += -fno-rtti -funwind-tables
+  ifneq ($(CONFIG_DEBUG_NOOPT),y)
+    ARCHOPTIMIZATION += -fno-strength-reduce
+  endif
+
+endif
+
+CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
 CPICFLAGS = $(ARCHPICFLAGS) $(CFLAGS)
-CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe -funwind-tables
+CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
 CXXPICFLAGS = $(ARCHPICFLAGS) $(CXXFLAGS)
 CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)
 AFLAGS = $(CFLAGS) -D__ASSEMBLY__
@@ -131,7 +149,6 @@ ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
 endif
 
 
-HOSTCC = gcc
 HOSTINCLUDES = -I.
 HOSTCFLAGS = -Wall -Wstrict-prototypes -Wshadow -Wundef -g -pipe
 HOSTLDFLAGS =