diff --git a/grub-core/lib/libgcrypt/cipher/rijndael.c b/grub-core/lib/libgcrypt/cipher/rijndael.c
index 559550b50..38e9a7c08 100644
--- a/grub-core/lib/libgcrypt/cipher/rijndael.c
+++ b/grub-core/lib/libgcrypt/cipher/rijndael.c
@@ -181,7 +181,8 @@ do_setkey (RIJNDAEL_context *ctx, const byte *key, const unsigned keylen)
   static int initialized = 0;
   static const char *selftest_failed=0;
   int rounds;
-  int i,j, r, t, rconpointer = 0;
+  unsigned int i;
+  int j, r, t, rconpointer = 0;
   int KC;
   union
   {