diff --git a/fs/fat/fat.c b/fs/fat/fat.c
index e65ef58..f8094d0 100644
--- a/fs/fat/fat.c
+++ b/fs/fat/fat.c
@@ -167,7 +167,7 @@
 
 	ret = f_write(f_file, buf, insize, &outsize);
 
-	debug("%s: %d %d %d %p\n", __func__, ret, insize, outsize, f_file);
+	debug("%s: %d %zd %d %p\n", __func__, ret, insize, outsize, f_file);
 
 	if (ret)
 		return ret;
@@ -260,7 +260,7 @@
 
 	ret = f_read(f_file, buf, insize, &outsize);
 
-	debug("%s: %d %d %d %p\n", __func__, ret, insize, outsize, f_file);
+	debug("%s: %d %zd %d %p\n", __func__, ret, insize, outsize, f_file);
 
 	if (ret)
 		return ret;