From aff77c86d6713098f5b59c04f862c85cc532a079 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 30 Jan 2020 17:09:29 +1100
Subject: [PATCH] HAL_ChibiOS: fixed bitmask error on storage erase

---
 libraries/AP_HAL_ChibiOS/Storage.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_HAL_ChibiOS/Storage.cpp b/libraries/AP_HAL_ChibiOS/Storage.cpp
index b9c7ae5882..f497e7510d 100644
--- a/libraries/AP_HAL_ChibiOS/Storage.cpp
+++ b/libraries/AP_HAL_ChibiOS/Storage.cpp
@@ -130,7 +130,10 @@ void Storage::_save_backup(void)
 */
 void Storage::_mark_dirty(uint16_t loc, uint16_t length)
 {
-    uint16_t end = loc + length;
+    if (length == 0) {
+        return;
+    }
+    uint16_t end = loc + length - 1;
     for (uint16_t line=loc>>CH_STORAGE_LINE_SHIFT;
          line <= end>>CH_STORAGE_LINE_SHIFT;
          line++) {