From defaea09b33884a4dd17f89e11c7a565605ae2d2 Mon Sep 17 00:00:00 2001
From: Tilman Sauerbeck <tilman@code-monkey.de>
Date: Fri, 3 Jan 2020 16:33:15 +0100
Subject: [PATCH] tools: Pad final chunks with 0xff if necessary.

The bootloader only accepts chunks whose size is a multiple of four.
---
 tools/update-firmware | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/update-firmware b/tools/update-firmware
index f610343..cd71124 100755
--- a/tools/update-firmware
+++ b/tools/update-firmware
@@ -168,6 +168,13 @@ class Application:
                 sys.stderr.write('File too large.\n')
                 return 3
 
+            # The bootloader only accepts chunks whose size is word-aligned:
+            num_extra = len(chunks[-1]) & 3
+
+            if num_extra != 0:
+                num_pad = 4 - extra
+                chunks[-1] += b'\xff' * num_pad
+
         # Defaulting to zero seems too dangerous:
         if self._offset is None:
             sector0 = None
-- 
2.30.2