diff --git a/firmware/ihex2fw.c b/firmware/ihex2fw.c
index 660b191..8f7fdaa9 100644
--- a/firmware/ihex2fw.c
+++ b/firmware/ihex2fw.c
@@ -250,19 +250,19 @@
 
 static int output_records(int outfd)
 {
-	unsigned char zeroes[5] = {0, 0, 0, 0, 0};
+	unsigned char zeroes[6] = {0, 0, 0, 0, 0, 0};
 	struct ihex_binrec *p = records;
 
 	while (p) {
 		uint16_t writelen = (p->len + 9) & ~3;
 
 		p->addr = htonl(p->addr);
-		p->len = htonl(p->len);
+		p->len = htons(p->len);
 		write(outfd, &p->addr, writelen);
 		p = p->next;
 	}
 	/* EOF record is zero length, since we don't bother to represent
 	   the type field in the binary version */
-	write(outfd, zeroes, 5);
+	write(outfd, zeroes, 6);
 	return 0;
 }