diff --git a/port/libusb/Makefile b/port/libusb/Makefile
index eeb82febc..52323c676 100644
--- a/port/libusb/Makefile
+++ b/port/libusb/Makefile
@@ -8,7 +8,7 @@ COMMON += btstack_audio_portaudio.c btstack_chipset_zephyr.c rijndael.c
 
 include ${BTSTACK_ROOT}/example/Makefile.inc
 
-CFLAGS  += -g -std=c99 -Wall -Wmissing-prototypes -Wstrict-prototypes -Wshadow -Wunused-parameter -Wredundant-decls -Wsign-compare
+CFLAGS  += -g -std=c99 -Wall -Wmissing-prototypes -Wstrict-prototypes -Wshadow -Wunused-parameter -Wredundant-decls -Wsign-compare -Wswitch-default
 # CFLAGS += -Werror
 # CFLAGS += -pedantic
 
diff --git a/test/pts/Makefile b/test/pts/Makefile
index 94ec2db04..42dfa001f 100644
--- a/test/pts/Makefile
+++ b/test/pts/Makefile
@@ -91,7 +91,7 @@ include ${BTSTACK_ROOT}/3rd-party/bluedroid/decoder/Makefile.inc
 include ${BTSTACK_ROOT}/3rd-party/bluedroid/encoder/Makefile.inc
 include ${BTSTACK_ROOT}/src/ble/gatt-service/Makefile.inc
 
-CFLAGS += -g -Wall -Wmissing-prototypes -Wstrict-prototypes -Wshadow -Wunused-variable -Wunused-parameter
+CFLAGS += -g -Wall -Wmissing-prototypes -Wstrict-prototypes -Wshadow -Wunused-variable -Wunused-parameter -Wswitch-default
 CFLAGS += -D ENABLE_TESTING_SUPPORT
 CFLAGS += -D ENABLE_LE_SIGNED_WRITE
 CFLAGS += -fsanitize=address -fno-omit-frame-pointer