From bc050fdeec9fb0c5cd98fa7a74fd7abc35d1124e Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Wed, 30 Oct 2019 21:46:06 +0800
Subject: [PATCH] bootloader: treat zero-length firmware in flash as no
 firmware

---
 artiq/firmware/bootloader/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/artiq/firmware/bootloader/main.rs b/artiq/firmware/bootloader/main.rs
index ea338c142..2c7e8a959 100644
--- a/artiq/firmware/bootloader/main.rs
+++ b/artiq/firmware/bootloader/main.rs
@@ -120,7 +120,7 @@ fn flash_boot() {
     let length = BigEndian::read_u32(&header[0..]) as usize;
     let expected_crc = BigEndian::read_u32(&header[4..]);
 
-    if length == 0xffffffff {
+    if length == 0 || length == 0xffffffff {
         println!("No firmware present");
         return
     } else if length > 4 * 1024 * 1024 {