diff --git a/sys/riotboot/slot.c b/sys/riotboot/slot.c
index cae8daca71..769028e61f 100644
--- a/sys/riotboot/slot.c
+++ b/sys/riotboot/slot.c
@@ -23,6 +23,7 @@
 
 #include <assert.h>
 #include <string.h>
+#include <inttypes.h>
 
 #include "cpu.h"
 #include "riotboot/slot.h"