diff --git a/firmware/Makefile b/firmware/Makefile
index 4c07383230..d577670a34 100644
--- a/firmware/Makefile
+++ b/firmware/Makefile
@@ -14,7 +14,7 @@ endif
 
 # Compiler options here.
 ifeq ($(USE_OPT),)
-  USE_OPT = $(EXTRA_PARAMS) $(DEBUG_LEVEL_OPT) $(RFLAGS) -fomit-frame-pointer -falign-functions=16 -Werror-implicit-function-declaration -Werror -Wno-error=pointer-sign -Wno-error=unused-function -Wno-error=unused-variable -Wno-error=sign-compare -Wno-error=unused-parameter -Wno-error=missing-field-initializers -Werror=type-limits -Wno-error=strict-aliasing -Wno-error=attributes
+  USE_OPT = $(EXTRA_PARAMS) $(DEBUG_LEVEL_OPT) $(RFLAGS) -fomit-frame-pointer -falign-functions=16 -Werror-implicit-function-declaration -Werror -Wno-error=pointer-sign -Wno-error=unused-function -Wno-error=unused-variable -Wno-error=sign-compare -Wno-error=unused-parameter -Wno-error=missing-field-initializers -Werror=type-limits -Wno-error=strict-aliasing -Wno-error=attributes -Wno-error=implicit-fallthrough
 endif
 
 # C specific options here (added to USE_OPT).