From 74f33d57c5ab5b7fc16dfc94727643b6aee76110 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sun, 12 Apr 2020 21:05:15 +1000
Subject: [PATCH] HAL_ChibiOS: avoid unnecessary H7 flash writes

---
 libraries/AP_HAL_ChibiOS/hwdef/common/flash.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/flash.c b/libraries/AP_HAL_ChibiOS/hwdef/common/flash.c
index 50806ae3bb..b25153fe1a 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/flash.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/flash.c
@@ -448,7 +448,8 @@ static bool stm32_flash_write_h7(uint32_t addr, const void *buf, uint32_t count)
     }
     stm32_flash_unlock();
     while (count >= 32) {
-        if (!stm32h7_flash_write32(addr, b)) {
+        if (memcmp((void*)addr, b, 32) != 0 &&
+            !stm32h7_flash_write32(addr, b)) {
             return false;
         }
         // check contents