Secure Bootloader USB Debug only works if there's no application in the flash

RE: Secure Bootloader USB Debug only works if there's no application in the flash

Cecylia — Fri, 17 May 2019 22:25:20 GMT

Got it, thanks!

RE: Secure Bootloader USB Debug only works if there's no application in the flash

Sigurd — Tue, 14 May 2019 09:23:46 GMT

When you power on the chip, the bootloader will check if it should enter DFU mode or not. There are several methods to enter DFU mode, and you can configure them in sdk_config.h. The different methods are documented here. If none of these methods have been used to activate DFU mode, the bootloader will check if the application is valid, and if it's valid, the bootloader will start the app.

The inactivity timer is used when you activate and enter DFU mode, and then you have the configured amount of ms to start the DFU, before the bootloader exits DFU mode, and tries to start the app again. If the non-debug bootloader does not start the app immediately, then one of the methods for entering DFU mode have been activated, OR the app that is on the chip is not valid.

[quote userid="12462" url="~/f/nordic-q-a/46886/secure-bootloader-usb-debug-only-works-if-there-s-no-application-in-the-flash"] I can only run the upgrade once, only if there's no application on the flash.[/quote]

You need a way to enter DFU mode. By default, the project have NRF_BL_DFU_ENTER_METHOD_BUTTON enabled, with NRF_BL_DFU_ENTER_METHOD_BUTTON_PIN set to 25. That means that you can hold down button 4 when you reset the board, and then the bootloader will enter DFU mode.

RE: Secure Bootloader USB Debug only works if there's no application in the flash

Cecylia — Tue, 07 May 2019 20:43:26 GMT

I did not add "DFU Trigger Library" to the application yet.

However, I forgot to tell you, actually I changed something in the bootloader. I changed the setting to
"#define NRF_BL_DFU_INACTIVITY_TIMEOUT_MS 10000"

In the non-debug version of the bootloader, it works as I intended. That is, when I plug in the Nordic to the USB, it will show up as "nrf52 sDFU USB" in the Device Manager for 10 seconds before it tries to go to application. So it gives me opportunity to update the FW within 10 seconds.

But in the debug version, it doesn't work the same way. Why? Should I prepare the application differently if I use Debug Bootloader?

RE: Secure Bootloader USB Debug only works if there's no application in the flash

Sigurd — Tue, 07 May 2019 15:33:16 GMT

Hi,

How are you entering DFU mode again after the first DFU ? Have you added the DFU Trigger Library to your application ? See this page.