diff --git a/stack/cmake/toolchains/gcc-arm-embedded.cmake b/stack/cmake/toolchains/gcc-arm-embedded.cmake
index 1d1995174..ad79f8359 100644
--- a/stack/cmake/toolchains/gcc-arm-embedded.cmake
+++ b/stack/cmake/toolchains/gcc-arm-embedded.cmake
@@ -41,8 +41,8 @@ SET(CMAKE_SYSTEM_VERSION 1)
 SET(CMAKE_CROSSCOMPILING 1)
 
 # set compiler flags to optimize for code size
-SET(CMAKE_C_FLAGS_DEBUG "-Og" CACHE STRING "")
-SET(CMAKE_C_FLAGS_RELEASE "-Os" CACHE STRING "")
+SET(CMAKE_C_FLAGS_DEBUG "-Og -Werror" CACHE STRING "")
+SET(CMAKE_C_FLAGS_RELEASE "-Os -Werror" CACHE STRING "")
 
 SET(TOOLCHAIN_DIR "" CACHE PATH "The directory containing all the cross compilation tools. (Compilation will fail if this is not set correctly)")