change it to PA6 as the bootload active pin.
#include <stdint.h>
#define FLASH_START_ADDR 0x00200000
-#define BOOTLOADER_BACKDOOR_ENABLE 0xF7FFFFFF // ENABLED: PORT A, PIN 6, LOW
+#define BOOTLOADER_BACKDOOR_ENABLE 0xF6FFFFFF // ENABLED: PORT A, PIN 6, LOW
#define BOOTLOADER_BACKDOOR_DISABLE 0xEFFFFFFF
#define SYS_CTRL_EMUOVR 0x400D20B4
#define SYS_CTRL_I_MAP 0x400D2098
