diff --git a/make/tools.mk b/make/tools.mk
index 71438f49d..a12dc50a3 100644
--- a/make/tools.mk
+++ b/make/tools.mk
@@ -278,7 +278,7 @@ else ifeq (,$(findstring _install,$(MAKECMDGOALS)))
   ifeq ($(GCC_VERSION),)
     $(error **ERROR** arm-none-eabi-gcc not in the PATH. Run 'make arm_sdk_install' to install automatically in the tools folder of this repo)
   else ifneq ($(GCC_VERSION), $(GCC_REQUIRED_VERSION))
-    $(error **WARNING** your arm-none-eabi-gcc is '$(GCC_VERSION)', but '$(GCC_REQUIRED_VERSION)' is expected. Run 'make arm_sdk_install' to install automatically in the tools folder of this repo)
+    $(error **ERROR** your arm-none-eabi-gcc is '$(GCC_VERSION)', but '$(GCC_REQUIRED_VERSION)' is expected. Override with 'GCC_REQUIRED_VERSION' in make/local.mk or run 'make arm_sdk_install' to install the right version automatically in the tools folder of this repo)
   endif
   # not installed, hope it's in the path...
   ARM_SDK_PREFIX ?= arm-none-eabi-