Application does not start beside DFU bootloader

[Massimo Pilia]

Hy everybody,

I'm trying to implement DFU bootloader in our custom board, starting from the "bootloader_secure_example", where I just changed leds and button pins in order to adapt them to our board. I successful flashed the soft device and the bootloader, merged with the bootloader settings, and I can perform a dfu firmware update with the nRF Connect, or nRF Toolbox, BLE app but, after the chip reset, nothing happens! No app advertising nor DFU_Targ. If I manually reset the board, pulling down the proper button, it returns to bootloader mode advertising with the DFU_Targ name. Even if I flash the firmware directly with keyl I see the same behavior.

There are no problems if I use just SD+APP (without bootloader).

I suppose the problem could be something related to rom/ram or bootloader settings.

Here are our settings:

SoftDevice: s13_nrf52_4.0.2
SDK: nRF5_SDK_13.1.0_7ca7556
Chip: nRF52832

Bootloader

IROM1 start: 0x78000
IROM1 size: 0x6000
IRAM1 start: 0x20002060
IRAM1 size: 0xDA70

Application

IROM1 start: 0x1F000
IROM1 size: 0x56000
IRAM1 start: 0x20003800
IRAM1 size: 0xC800

Bootloader settings script

nrfutil settings generate --family NRF52 --application-version 4 --bootloader-version 1 --bl-settings-version 1 bootloader_settings.hex

Bootloader DFU Settings:
* File:                 bootloader_settings.hex
* Family:               nRF52
* CRC:                  0xC90C83B3
* Settings Version:     0x00000001 (1)
* App Version:          0x00000004 (4)
* Bootloader Version:   0x00000001 (1)
* Bank Layout:          0x00000000
* Current Bank:         0x00000000
* Application Size:     0x00000000 (0 bytes)
* Application CRC:      0x00000000
* Bank0 Bank Code:      0x00000001

Merged hex files

mergehex --merge bootloader_settings.hex Bootloader.hex --output Bootloader_with_settings.hex

I tried also to set the variable m_dfu_settings_buffer in the file nrf_dfu_settings.c in this way:

uint8_t  m_dfu_settings_buffer[CODE_PAGE_SIZE] __attribute__((at(BOOTLOADER_SETTINGS_ADDRESS)))
                                                   __attribute__((used)) = {NRF_DFU_BANK_VALID_APP};

but when I try to merge bootloader and bootloader-settings .hex files it returns the error

ERROR: The hex files cannot be merged since there are conflicts.

Any suggestion?

Thanks in advance.

Massimo

[Stian Røed Hafskjold]

You only need to generate the settings page if you plan on flashing the application using a programmer instead of uploading it through the DFU. If you upload the application through the DFU the bootloader automatically creates the settings page.

Can you try to only flash SD and bootloader, and then upload the application using nRF Connect or similar, and see if that works?

[Stian Røed Hafskjold]

Hi, I had a look at your hex files, and I can also get the application to work but not app+BL. I think I found the issue. In your application you are using pin P21. This is the reset pin. Since your application is not configuring this as a reset pin, it works fine as a regular GPIO. However, the bootloader configures this as the reset pin (writing to the PSELRESET registers), so then your application will not start if this pin is used as a GPIO.

You can go to the bootloader project and remove the CONFIG_GPIO_AS_PINRESET define in the project settings. This should get you a bit further. Let me know if things still don't work. In that case maybe you can post your application project as well.