--- a/loadtools/romload.c	Sat Feb 29 23:53:33 2020 +0000
+++ b/loadtools/romload.c	Sun Mar 01 00:57:12 2020 +0000
@@ -150,6 +150,38 @@
 	return 0;
 }
 
+static int
+expect_add_response(buf, expect_bytes, timeout)
+	u_char *buf;
+{
+	fd_set fds;
+	struct timeval tv;
+	int pass, cc;
+
+	for (pass = 0; pass < expect_bytes; ) {
+		FD_ZERO(&fds);
+		FD_SET(target_fd, &fds);
+		tv.tv_sec = 0;
+		tv.tv_usec = timeout * 1000;
+		cc = select(target_fd+1, &fds, NULL, NULL, &tv);
+		if (cc < 0) {
+			if (errno == EINTR)
+				continue;
+			perror("select");
+			exit(1);
+		}
+		if (cc < 1)
+			return(-1);
+		cc = read(target_fd, buf + pass, expect_bytes - pass);
+		if (cc <= 0) {
+			perror("read after successful select");
+			exit(1);
+		}
+		pass += cc;
+	}
+	return(0);
+}
+
 static uint32_t
 compute_block_cksum()
 {
@@ -168,6 +200,7 @@
 	int resp;
 	uint16_t image_cksum;
 	unsigned long rec_count;
+	u_char addresp[2];
 	static int zero = 0;
 
 	if (open_srec_file(&iramimage) < 0)
@@ -195,6 +228,12 @@
 				resp);
 		exit(1);
 	}
+	resp = expect_add_response(addresp, 2, INTERMEDIATE_TIMEOUT);
+	if (resp < 0 || addresp[0] != 0x00 || addresp[1] != 0x04) {
+		fprintf(stderr,
+		"error: extra bytes after >p not received as expected\n");
+		exit(1);
+	}
 	printf("<p command successful, switching to %s baud\n",
 		romload_baud_rate->name);
 	set_serial_baudrate(romload_baud_rate);
@@ -290,6 +329,12 @@
 				resp);
 		exit(1);
 	}
+	resp = expect_add_response(addresp, 1, INTERMEDIATE_TIMEOUT);
+	if (resp < 0) {
+		fprintf(stderr,
+		"error: extra byte after >c not received as expected\n");
+		exit(1);
+	}
 	printf("<c command successful, sending <b\n");
 
 	bcopy(iramimage.record + 1, branch_cmd + 2, 4);