diff --git a/make/defs-cpp.mk b/make/defs-cpp.mk
index 9f98e46d..f0de5cd5 100644
--- a/make/defs-cpp.mk
+++ b/make/defs-cpp.mk
@@ -45,9 +45,9 @@ EXPORT_PROJECT_LIB          ?= $(USE_PROJECT_LIB)
 USE_JW_BUILD                ?= true
 USE_EXCEPTIONS_IN_C         ?= true
 
-USE_COMPILER_OPTIMIZATION_OPTS = false
-USE_COMPILER_DEBUG_OPTS      = true
-COMPILE_DEBUG_CODE           = true
+USE_COMPILER_OPTIMIZATION_OPTS ?= false
+USE_COMPILER_DEBUG_OPTS      ?= true
+COMPILE_DEBUG_CODE           ?= true
 
 BUILD_CFLAGS                += $(CFLAGS)
 BUILD_CXXFLAGS              += $(CXXFLAGS)
@@ -184,7 +184,9 @@ ifeq ($(TARGET_TRIPLET),arm-none-eabi)
   USE_DISABLE_COMPILER_OPTIMISATION_OPTS = false
   USE_EXCEPTIONS_IN_C        = false
   ARM_NONE_EABI_ALLFLAGS    += -fno-exceptions
-  ARM_NONE_EABI_ALLFLAGS    += -Os
+  ifeq ($(USE_DISABLE_COMPILER_OPTIMISATION_OPTS),true)
+    ARM_NONE_EABI_ALLFLAGS  += -Os
+  endif
   BUILD_LDFLAGS             += $(ARM_NONE_EABI_ALLFLAGS)
   BUILD_CPPFLAGS            += $(ARM_NONE_EABI_ALLFLAGS)
   BUILD_CXXFLAGS            += -fno-rtti
@@ -246,7 +248,6 @@ ifeq ($(TARGET_TRIPLET),arm-none-eabi)
   #BUILD_CXXFLAGS           += -fno-move-loop-invariants
   #BUILD_CPPFLAGS           += -fno-split-wide-types
   #BUILD_CPPFLAGS           += -fno-tree-loop-optimize
-  #BUILD_CPPFLAGS           += -Og
 
   #BUILD_CPPFLAGS           += -fno-exceptions
   #BUILD_CXXFLAGS           += -fno-rtti
@@ -514,6 +515,10 @@ ifeq ($(USE_COMPILER_DEBUG_OPTS),true)
   #BUILD_EXTRA_DEBUG_FLAGS  += -gdwarf-2
   BUILD_CPPFLAGS            += -g3 $(BUILD_EXTRA_DEBUG_FLAGS)
   BUILD_LDFLAGS             += -g3 $(BUILD_EXTRA_DEBUG_FLAGS)
+  ifneq ($(USE_COMPILER_OPTIMIZATION_OPTS),true)
+    BUILD_CPPFLAGS          += -Og
+    BUILD_LDFLAGS           += -Og
+  endif
 endif
 
 ifeq ($(CC),$(GCC))