Fix bootloaders not starting user application if the HWB is grounded during watchdog reset.

2 files changed, 13 insertions, 8 deletions

diff --git a/Bootloaders/MassStorage/BootloaderMassStorage.c b/Bootloaders/MassStorage/BootloaderMassStorage.c
index afbc25014..2765e2c20 100644
--- a/Bootloaders/MassStorage/BootloaderMassStorage.c
+++ b/Bootloaders/MassStorage/BootloaderMassStorage.c
@@ -120,8 +120,19 @@ void Application_Jump_Check(void)
 			if (!(MCUSR & (1 << EXTRF)) || (MagicBootKey == MAGIC_BOOT_KEY))
 			  JumpToApplication = true;
 
+			/* Clear reset source */
 			MCUSR &= ~(1 << EXTRF);
 		}
+		else
+		{
+			/* If the reset source was the bootloader and the key is correct, clear it and jump to the application;
+			 * this can happen in the HWBE fuse is set, and the HBE pin is low during the watchdog reset */
+			if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
+				JumpToApplication = true;
+
+			/* Clear reset source */
+			MCUSR &= ~(1 << WDRF);
+		}
 	#endif
 
 	/* Don't run the user application if the reset vector is blank (no app loaded) */
diff --git a/Bootloaders/MassStorage/BootloaderMassStorage.txt b/Bootloaders/MassStorage/BootloaderMassStorage.txt
index 467972cc4..190ff4a3e 100644
--- a/Bootloaders/MassStorage/BootloaderMassStorage.txt
+++ b/Bootloaders/MassStorage/BootloaderMassStorage.txt
@@ -67,9 +67,9 @@
  *
  *  The are two behaviours of this bootloader, depending on the device's fuses:
  *
- *  <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is not reset from
+ *  <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is reset from
  *  the external reset pin, unless no valid user application has been loaded. To initiate the bootloader, the
- *  device's external reset pin should be grounded.
+ *  device's external reset pin should be grounded momentarily.
  *
  *  <b>If the device's BOOTRST fuse is not set</b>, the bootloader will run only if initiated via a software
  *  jump, or if the \c HWB pin was low during the last device reset (if the \c HWBE fuse is set).
@@ -206,12 +206,6 @@
  *  Mass Storage bootloader, or the file system synced via an appropriate command
  *  (such as the OS's normal disk ejection command) before disconnecting the device.
  *
- *  \par After loading an application, it is not run automatically on startup.
- *  Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader
- *  to run automatically when the device is reset. In most cases, the BOOTRST
- *  fuse should be disabled and the HWBE fuse used instead to run the bootloader
- *  when needed.
- *
  *  \section Sec_Options Project Options
  *
  *  The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.