diff --git a/boards/arduino-common/Makefile.include b/boards/arduino-common/Makefile.include
index e41cc78bed..753113bd17 100644
--- a/boards/arduino-common/Makefile.include
+++ b/boards/arduino-common/Makefile.include
@@ -37,7 +37,7 @@ endif
 # define build specific options
 export CFLAGS_CPU   = -mmcu=atmega328p  $(CFLAGS_FPU)
 export CFLAGS_LINK  = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
-export CFLAGS_DBG   = -ggdb -g3
+export CFLAGS_DBG  ?= -ggdb -g3
 export CFLAGS_OPT  ?= -Os
 
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
diff --git a/boards/arduino-mega2560/Makefile.include b/boards/arduino-mega2560/Makefile.include
index bc4c8611e0..601a6b2a4a 100644
--- a/boards/arduino-mega2560/Makefile.include
+++ b/boards/arduino-mega2560/Makefile.include
@@ -36,7 +36,7 @@ endif
 # define build specific options
 export CFLAGS_CPU   = -mmcu=atmega2560  $(CFLAGS_FPU)
 export CFLAGS_LINK  = -fno-builtin -fshort-enums
-export CFLAGS_DBG   = -ggdb -g3
+export CFLAGS_DBG  ?= -ggdb -g3
 export CFLAGS_OPT  ?= -Os
 
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
diff --git a/boards/msba2-common/Makefile.include b/boards/msba2-common/Makefile.include
index bbf7290376..cfad49ba83 100644
--- a/boards/msba2-common/Makefile.include
+++ b/boards/msba2-common/Makefile.include
@@ -6,7 +6,7 @@ TERMPROG ?= $(RIOTBASE)/dist/tools/pyterm/pyterm
 
 export CFLAGS_CPU   = -mcpu=arm7tdmi-s
 export CFLAGS_LINK  = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
-export CFLAGS_DBG   = -ggdb -g3
+export CFLAGS_DBG  ?= -ggdb -g3
 export CFLAGS_OPT  ?= -Os
 
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
diff --git a/boards/waspmote-pro/Makefile.include b/boards/waspmote-pro/Makefile.include
index 2ba8c80afe..54a9bb1d2d 100644
--- a/boards/waspmote-pro/Makefile.include
+++ b/boards/waspmote-pro/Makefile.include
@@ -46,7 +46,7 @@ endif
 # define build specific options
 export CFLAGS_CPU   = -mmcu=atmega1281  $(CFLAGS_FPU)
 export CFLAGS_LINK  = -fno-builtin -fshort-enums
-export CFLAGS_DBG   = -ggdb -g3
+export CFLAGS_DBG  ?= -ggdb -g3
 export CFLAGS_OPT  ?= -Os
 
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
diff --git a/cpu/Makefile.include.cortexm_common b/cpu/Makefile.include.cortexm_common
index c91b637b6c..e46b851576 100644
--- a/cpu/Makefile.include.cortexm_common
+++ b/cpu/Makefile.include.cortexm_common
@@ -9,7 +9,7 @@ ifneq (llvm,$(TOOLCHAIN))
 export CFLAGS_CPU  += -mno-thumb-interwork
 endif
 export CFLAGS_LINK  = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
-export CFLAGS_DBG   = -ggdb -g3
+export CFLAGS_DBG  ?= -ggdb -g3
 export CFLAGS_OPT  ?= -Os
 
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)
diff --git a/cpu/Makefile.include.msp430_common b/cpu/Makefile.include.msp430_common
index b58b58e065..88b0450cfa 100644
--- a/cpu/Makefile.include.msp430_common
+++ b/cpu/Makefile.include.msp430_common
@@ -4,7 +4,7 @@ export TARGET_ARCH ?= msp430
 # define build specific options
 CFLAGS_CPU   = -mmcu=$(CPU_MODEL) -std=gnu99
 CFLAGS_LINK  = -ffunction-sections -fdata-sections
-CFLAGS_DBG   = -gdwarf-2
+CFLAGS_DBG  ?= -gdwarf-2
 CFLAGS_OPT  ?= -Os
 # export compiler flags
 export CFLAGS += $(CFLAGS_CPU) $(CFLAGS_LINK) $(CFLAGS_DBG) $(CFLAGS_OPT)