diff --git a/stm-firmware/Makefile b/stm-firmware/Makefile
index 909192a..d1ec8f0 100644
--- a/stm-firmware/Makefile
+++ b/stm-firmware/Makefile
@@ -60,7 +60,7 @@ LFLAGS += -Tstm32f407vet6_flash.ld -Wl,-Map=$(mapfile).map
 
 CFLAGS = -c -fmessage-length=0 -mlittle-endian -mthumb -mcpu=cortex-m4 -mthumb-interwork
 CFLAGS += -mfloat-abi=hard -mfpu=fpv4-sp-d16 -nostartfiles -O0 -g
-CFLAGS += -Wall -Wextra -Wold-style-declaration -Wuninitialized -Wmaybe-uninitialized -Wunused-parameter
+CFLAGS += -Wall -Wextra -Wold-style-declaration -Wuninitialized -Wmaybe-uninitialized -Wunused-parameter -Wimplicit-fallthrough=3 -Wsign-compare
 ####################################################################################
 
 OBJ = $(CFILES:%.c=$(OBJDIR)/%.c.o)
diff --git a/stm-firmware/shell.c b/stm-firmware/shell.c
index 97d14a0..bbfbed6 100644
--- a/stm-firmware/shell.c
+++ b/stm-firmware/shell.c
@@ -138,7 +138,7 @@ static shellmatta_retCode_t shell_cmd_pt1000_res(const shellmatta_handle_t   han
 		temp_prefix = "<";
 		break;
 	case 0:
-		/* Expected fallthrough */
+		/* FALLTHRU */
 	default:
 		temp_prefix = "";
 		break;