diff --git a/jtagmkI.c b/jtagmkI.c
index f019115d..bd52b36e 100644
--- a/jtagmkI.c
+++ b/jtagmkI.c
@@ -542,7 +542,7 @@ static unsigned char jtagmkI_get_baud(long baud)
 static int jtagmkI_initialize(PROGRAMMER * pgm, AVRPART * p)
 {
   AVRMEM hfuse;
-  char cmd[1], resp[2];
+  char cmd[1], resp[5];
   unsigned char b;
 
   if (!(p->flags & AVRPART_HAS_JTAG)) {