diff --git a/tools/kwboot.c b/tools/kwboot.c
index 2683e53..1ba5ded 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -465,7 +465,7 @@
 	ssize_t nin, nout;
 	char _buf[128], *buf = _buf;
 
-	nin = read(in, buf, sizeof(buf));
+	nin = read(in, buf, sizeof(_buf));
 	if (nin <= 0)
 		return -1;