Don't run user application in the bootloader unless a valid app is present (thanks...

[pub/USBasp.git] / Bootloaders / MassStorage / BootloaderMassStorage.c

diff --git a/Bootloaders/MassStorage/BootloaderMassStorage.c b/Bootloaders/MassStorage/BootloaderMassStorage.c
index cfe0cdb..191d49e 100644 (file)
--- a/Bootloaders/MassStorage/BootloaderMassStorage.c
+++ b/Bootloaders/MassStorage/BootloaderMassStorage.c
@@ -116,13 +116,22 @@ void Application_Jump_Check(void)
 
        /* If the reset source was the bootloader and the key is correct, clear it and jump to the application */
        if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
-       {
-               MagicBootKey      = 0;
-               JumpToApplication = true;
-       }
+         JumpToApplication |= true;
+
+       /* Don't run the user application if the reset vector is blank (no app loaded) */
+       if (pgm_read_word_near(0) == 0xFFFF)
+         JumpToApplication = false;
 
+       /* If a request has been made to jump to the user application, honor it */
        if (JumpToApplication)
        {
+               /* Turn off the watchdog */
+               MCUSR &= ~(1<<WDRF);
+               wdt_disable();
+
+               /* Clear the boot key and jump to the user application */
+               MagicBootKey = 0;
+
                // cppcheck-suppress constStatement
                ((void (*)(void))0x0000)();
        }