diff --git a/Makefile.inc b/Makefile.inc
index 28f136313144..2cad2304d5f1 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -401,7 +401,7 @@ endif
 
 CFLAGS_common += -pipe -g -nostdinc -std=gnu11
 CFLAGS_common += -nostdlib -Wall -Wundef -Wstrict-prototypes -Wmissing-prototypes
-CFLAGS_common += -Wwrite-strings -Wredundant-decls -Wno-trigraphs
+CFLAGS_common += -Wwrite-strings -Wredundant-decls -Wno-trigraphs -Wimplicit-fallthrough
 CFLAGS_common += -Wstrict-aliasing -Wshadow -Wdate-time -Wtype-limits
 CFLAGS_common += -fno-common -ffreestanding -fno-builtin -fomit-frame-pointer
 CFLAGS_common += -ffunction-sections -fdata-sections -fno-pie