diff --git a/Tools/AP_Bootloader/AP_Bootloader.cpp b/Tools/AP_Bootloader/AP_Bootloader.cpp
index 41a1c4ad7b..78eeff4ac9 100644
--- a/Tools/AP_Bootloader/AP_Bootloader.cpp
+++ b/Tools/AP_Bootloader/AP_Bootloader.cpp
@@ -51,9 +51,9 @@ int main(void)
 {
     board_info.board_type = APJ_BOARD_ID;
     board_info.board_rev = 0;
-    board_info.fw_size = (BOARD_FLASH_SIZE - FLASH_BOOTLOADER_LOAD_KB)*1024;
+    board_info.fw_size = (BOARD_FLASH_SIZE - (FLASH_BOOTLOADER_LOAD_KB + FLASH_RESERVE_END_KB))*1024;
     if (BOARD_FLASH_SIZE > 1024 && check_limit_flash_1M()) {
-        board_info.fw_size = (1024 - FLASH_BOOTLOADER_LOAD_KB)*1024;        
+        board_info.fw_size = (1024 - FLASH_BOOTLOADER_LOAD_KB)*1024;
     }
 
     bool try_boot = false;
diff --git a/Tools/AP_Bootloader/support.cpp b/Tools/AP_Bootloader/support.cpp
index eef6cb941e..f37b413b77 100644
--- a/Tools/AP_Bootloader/support.cpp
+++ b/Tools/AP_Bootloader/support.cpp
@@ -80,11 +80,22 @@ void flash_init(void)
 {
     uint32_t reserved = 0;
     num_pages = stm32_flash_getnumpages();
+    /*
+      advance flash_base_page to account for FLASH_BOOTLOADER_LOAD_KB
+     */
     while (reserved < FLASH_BOOTLOADER_LOAD_KB * 1024U &&
            flash_base_page < num_pages) {
         reserved += stm32_flash_getpagesize(flash_base_page);
         flash_base_page++;
     }
+    /*
+      reduce num_pages to account for FLASH_RESERVE_END_KB
+     */
+    reserved = 0;
+    while (reserved < FLASH_RESERVE_END_KB * 1024U) {
+        reserved += stm32_flash_getpagesize(num_pages-1);
+        num_pages--;
+    }
 }
 
 void flash_set_keep_unlocked(bool set)