bootloader cannot start app

[djqtsg]

HW: BMD-350

SDK: nRF5_SDK_12.0.0_12f24da

Sample Code: examples\dfu\bootloader_secure\pca10040_debug

I have my own firmware app.

Problem:

If I use Keil to flash bootloader, it can start the app. If I power off and then on, it cannot and get stuck at nrf_bootloader_app_start_impl.

[djqtsg]

If I power on the device, bootloader cannot start my app; however, if I press reset button, it can.

[Hung Bui]

Hi,

Please describe step by step how you tested.

Especially how you flash your application. Have you used the bootloader to OTA your application ? If you haven't, please do.

Have you tried to test with an SDK example as application ?

[djqtsg]

1. yes, I have no problem with the bootloader to do OTA. My app CAN be started as long as I don't power off the device, which is made by us with BMD 350 and a few SPI, I2C sensors.

2. I have tried to test an app which I combined sample UART and DFU service into; and the bootloader is able to start it in the case power off and on.

[Hung Bui]

How do you know that it's stuck at nrf_bootloader_app_start_impl() ? if you simply couldn't step through that when debugging then it's normal. That function branch to application, you can't step through that, or you can but the debugger woudn't know the code in the application.

What you can do is to try putting a notification when your application start, for example turn on an LED. Just to check if it's branched to the application or not, or you can use debugger in your application to wait for the bootloader branch to the application.

I don't see any reason why the bootloader can't branch to application when power up but can when doing reset.

Could you check if it's related to any peripherals on your board that can't bootup quickly and may have a problem ?

You can try to comment out part of your code, as you can see that normal application can boot without problem.

[djqtsg]

yes, your are right.

my app gets stuck at some initialization stage, most likely uart_init, which is the first function being called. If I add some delay before it, the app can be started.