diff --git a/cpu/arm7_common/Makefile.include b/cpu/arm7_common/Makefile.include
index 27cb4aee00..f919daca78 100644
--- a/cpu/arm7_common/Makefile.include
+++ b/cpu/arm7_common/Makefile.include
@@ -9,7 +9,7 @@ INCLUDES += -I$(RIOTBASE)/cpu/arm7_common/include/
 MCPU ?= arm7tdmi-s
 
 CFLAGS_CPU  = -mcpu=$(MCPU)
-CFLAGS_LINK = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
+CFLAGS_LINK = -ffunction-sections -fdata-sections -fshort-enums
 CFLAGS_DBG  ?= -ggdb -g3
 CFLAGS_OPT  ?= -Os
 
diff --git a/makefiles/arch/cortexm.inc.mk b/makefiles/arch/cortexm.inc.mk
index 8839277682..436b923a46 100644
--- a/makefiles/arch/cortexm.inc.mk
+++ b/makefiles/arch/cortexm.inc.mk
@@ -20,7 +20,7 @@ ifneq (llvm,$(TOOLCHAIN))
   endif
 endif
 
-CFLAGS_LINK  = -ffunction-sections -fdata-sections -fno-builtin -fshort-enums
+CFLAGS_LINK  = -ffunction-sections -fdata-sections -fshort-enums
 CFLAGS_DBG  ?= -ggdb -g3
 CFLAGS_OPT  ?= -Os