Crashing at ble_dfu_buttonless_async_svci_init()

[theslawek]

IC: NRF52840 on PCA100059 (Dongle)
SDK:15.0.0
SD: s140_nrf52_6.0.0_softdevice.hex
Bootloader: '\pca10056_ble_debug' from SDK examples with custom public_key.c
Environment: Windows and VScode

Recently migrated this codebase from nRF52832 to nRF52840.

UICR is erased every flash. Reboot after flash doesn't help.

I've had to disabled DFU initialization because it crashes the app with these two last lines. "-DDEGUG" is present in Makefile, but no more info is given.

<info> app: BLE init
<info> app: Setting vector table to bootloader: 0x000F1000
<info> app: Setting vector table to main app: 0x00026000

My DFU init code (that needs to be disabled to not crash)

// Initialize the async SVCI interface to bootloader.
err_code = ble_dfu_buttonless_async_svci_init();
APP_ERROR_CHECK(err_code);

dfus_init.evt_handler = ble_dfu_evt_handler;

err_code = ble_dfu_buttonless_init(&dfus_init);
APP_ERROR_CHECK(err_code);

When I add some debug console printing, the crash seems to happen a few moments AFTER setting the vector address. Is this interrupt related?

The vector addresses seem to correlate.

ble_app_blinky_gcc_nrf52.ld

/* Linker script to configure memory regions. */

SEARCH_DIR(.)
GROUP(-lgcc -lc -lnosys)

MEMORY
{
  FLASH (rx) : ORIGIN = 0x26000, LENGTH = 0xda000
  RAM (rwx) :  ORIGIN = 0x200022e0, LENGTH = 0x3dd20
}

SECTIONS
{
}

SECTIONS
{
  . = ALIGN(4);
  .mem_section_dummy_ram :
  {
  }
  .log_dynamic_data :
  {
    PROVIDE(__start_log_dynamic_data = .);
    KEEP(*(SORT(.log_dynamic_data*)))
    PROVIDE(__stop_log_dynamic_data = .);
  } > RAM
  .cli_sorted_cmd_ptrs :
  {
    PROVIDE(__start_cli_sorted_cmd_ptrs = .);
    KEEP(*(.cli_sorted_cmd_ptrs))
    PROVIDE(__stop_cli_sorted_cmd_ptrs = .);
  } > RAM
  .fs_data :
  {
    PROVIDE(__start_fs_data = .);
    KEEP(*(.fs_data))
    PROVIDE(__stop_fs_data = .);
  } > RAM

} INSERT AFTER .data;

SECTIONS
{
  .mem_section_dummy_rom :
  {
  }
  .sdh_soc_observers :
  {
    PROVIDE(__start_sdh_soc_observers = .);
    KEEP(*(SORT(.sdh_soc_observers*)))
    PROVIDE(__stop_sdh_soc_observers = .);
  } > FLASH
  .pwr_mgmt_data :
  {
    PROVIDE(__start_pwr_mgmt_data = .);
    KEEP(*(SORT(.pwr_mgmt_data*)))
    PROVIDE(__stop_pwr_mgmt_data = .);
  } > FLASH
  .sdh_ble_observers :
  {
    PROVIDE(__start_sdh_ble_observers = .);
    KEEP(*(SORT(.sdh_ble_observers*)))
    PROVIDE(__stop_sdh_ble_observers = .);
  } > FLASH
  .log_const_data :
  {
    PROVIDE(__start_log_const_data = .);
    KEEP(*(SORT(.log_const_data*)))
    PROVIDE(__stop_log_const_data = .);
  } > FLASH
    .nrf_balloc :
  {
    PROVIDE(__start_nrf_balloc = .);
    KEEP(*(.nrf_balloc))
    PROVIDE(__stop_nrf_balloc = .);
  } > FLASH
  .sdh_state_observers :
  {
    PROVIDE(__start_sdh_state_observers = .);
    KEEP(*(SORT(.sdh_state_observers*)))
    PROVIDE(__stop_sdh_state_observers = .);
  } > FLASH
  .sdh_stack_observers :
  {
    PROVIDE(__start_sdh_stack_observers = .);
    KEEP(*(SORT(.sdh_stack_observers*)))
    PROVIDE(__stop_sdh_stack_observers = .);
  } > FLASH
  .sdh_req_observers :
  {
    PROVIDE(__start_sdh_req_observers = .);
    KEEP(*(SORT(.sdh_req_observers*)))
    PROVIDE(__stop_sdh_req_observers = .);
  } > FLASH
    .nrf_queue :
  {
    PROVIDE(__start_nrf_queue = .);
    KEEP(*(.nrf_queue))
    PROVIDE(__stop_nrf_queue = .);
  } > FLASH
    .cli_command :
  {
    PROVIDE(__start_cli_command = .);
    KEEP(*(.cli_command))
    PROVIDE(__stop_cli_command = .);
  } > FLASH
  .crypto_data :
  {
    PROVIDE(__start_crypto_data = .);
    KEEP(*(SORT(.crypto_data*)))
    PROVIDE(__stop_crypto_data = .);
  } > FLASH

} INSERT AFTER .text

INCLUDE "nrf_common.ld"

secure_bootloader_gcc_nrf52.ld

/* Linker script to configure memory regions. */

SEARCH_DIR(.)
GROUP(-lgcc -lc -lnosys)

MEMORY
{
  FLASH (rx) : ORIGIN = 0xf1000, LENGTH = 0xd000
  RAM (rwx) :  ORIGIN = 0x200057b8, LENGTH = 0x3a848
  uicr_mbr_params_page (r) : ORIGIN = 0x10001018, LENGTH = 0x4
  mbr_params_page (r) : ORIGIN = 0x000FE000, LENGTH = 0x1000
  bootloader_settings_page (r) : ORIGIN = 0x000FF000, LENGTH = 0x1000
  uicr_bootloader_start_address (r) : ORIGIN = 0x10001014, LENGTH = 0x4
}

SECTIONS
{
  .uicr_mbr_params_page :
  {
    PROVIDE(__start_uicr_mbr_params_page = .);
    KEEP(*(SORT(.uicr_mbr_params_page*)))
    PROVIDE(__stop_uicr_mbr_params_page = .);
  } > uicr_mbr_params_page
  .mbr_params_page(NOLOAD) :
  {
    PROVIDE(__start_mbr_params_page = .);
    KEEP(*(SORT(.mbr_params_page*)))
    PROVIDE(__stop_mbr_params_page = .);
  } > mbr_params_page
  .bootloader_settings_page(NOLOAD) :
  {
    PROVIDE(__start_bootloader_settings_page = .);
    KEEP(*(SORT(.bootloader_settings_page*)))
    PROVIDE(__stop_bootloader_settings_page = .);
  } > bootloader_settings_page
  .uicr_bootloader_start_address :
  {
    PROVIDE(__start_uicr_bootloader_start_address = .);
    KEEP(*(SORT(.uicr_bootloader_start_address*)))
    PROVIDE(__stop_uicr_bootloader_start_address = .);
  } > uicr_bootloader_start_address
}

SECTIONS
{
  . = ALIGN(4);
  .mem_section_dummy_ram :
  {
  }
  .log_dynamic_data :
  {
    PROVIDE(__start_log_dynamic_data = .);
    KEEP(*(SORT(.log_dynamic_data*)))
    PROVIDE(__stop_log_dynamic_data = .);
  } > RAM
  .fs_data :
  {
    PROVIDE(__start_fs_data = .);
    KEEP(*(.fs_data))
    PROVIDE(__stop_fs_data = .);
  } > RAM

} INSERT AFTER .data;

SECTIONS
{
  .mem_section_dummy_rom :
  {
  }
  .crypto_data :
  {
    PROVIDE(__start_crypto_data = .);
    KEEP(*(SORT(.crypto_data*)))
    PROVIDE(__stop_crypto_data = .);
  } > FLASH
    .nrf_queue :
  {
    PROVIDE(__start_nrf_queue = .);
    KEEP(*(.nrf_queue))
    PROVIDE(__stop_nrf_queue = .);
  } > FLASH
  .dfu_trans :
  {
    PROVIDE(__start_dfu_trans = .);
    KEEP(*(SORT(.dfu_trans*)))
    PROVIDE(__stop_dfu_trans = .);
  } > FLASH
  .log_const_data :
  {
    PROVIDE(__start_log_const_data = .);
    KEEP(*(SORT(.log_const_data*)))
    PROVIDE(__stop_log_const_data = .);
  } > FLASH
    .nrf_balloc :
  {
    PROVIDE(__start_nrf_balloc = .);
    KEEP(*(.nrf_balloc))
    PROVIDE(__stop_nrf_balloc = .);
  } > FLASH
    .svc_data :
  {
    PROVIDE(__start_svc_data = .);
    KEEP(*(.svc_data))
    PROVIDE(__stop_svc_data = .);
  } > FLASH
  .sdh_ble_observers :
  {
    PROVIDE(__start_sdh_ble_observers = .);
    KEEP(*(SORT(.sdh_ble_observers*)))
    PROVIDE(__stop_sdh_ble_observers = .);
  } > FLASH
  .sdh_state_observers :
  {
    PROVIDE(__start_sdh_state_observers = .);
    KEEP(*(SORT(.sdh_state_observers*)))
    PROVIDE(__stop_sdh_state_observers = .);
  } > FLASH
  .sdh_stack_observers :
  {
    PROVIDE(__start_sdh_stack_observers = .);
    KEEP(*(SORT(.sdh_stack_observers*)))
    PROVIDE(__stop_sdh_stack_observers = .);
  } > FLASH
  .sdh_req_observers :
  {
    PROVIDE(__start_sdh_req_observers = .);
    KEEP(*(SORT(.sdh_req_observers*)))
    PROVIDE(__stop_sdh_req_observers = .);
  } > FLASH
  .sdh_soc_observers :
  {
    PROVIDE(__start_sdh_soc_observers = .);
    KEEP(*(SORT(.sdh_soc_observers*)))
    PROVIDE(__stop_sdh_soc_observers = .);
  } > FLASH

} INSERT AFTER .text

INCLUDE "nrf_common.ld"

/modules/nrfx/mdk/gcc_startup_nrf52840.S

/*
 
Copyright (c) 2009-2018 ARM Limited. All rights reserved.

    SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the License); you may
not use this file except in compliance with the License.
You may obtain a copy of the License at

    www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an AS IS BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

NOTICE: This file has been modified by Nordic Semiconductor ASA.

*/

    .syntax unified
    .arch armv7e-m

#ifdef __STARTUP_CONFIG
#include "startup_config.h"
#ifndef __STARTUP_CONFIG_STACK_ALIGNEMENT
#define __STARTUP_CONFIG_STACK_ALIGNEMENT 3
#endif
#endif

    .section .stack
#if defined(__STARTUP_CONFIG)
    .align __STARTUP_CONFIG_STACK_ALIGNEMENT
    .equ    Stack_Size, __STARTUP_CONFIG_STACK_SIZE
#elif defined(__STACK_SIZE)
    .align 3
    .equ    Stack_Size, __STACK_SIZE
#else
    .align 3
    .equ    Stack_Size, 8192
#endif
    .globl __StackTop
    .globl __StackLimit
__StackLimit:
    .space Stack_Size
    .size __StackLimit, . - __StackLimit
__StackTop:
    .size __StackTop, . - __StackTop

    .section .heap
    .align 3
#if defined(__STARTUP_CONFIG)
    .equ Heap_Size, __STARTUP_CONFIG_HEAP_SIZE
#elif defined(__HEAP_SIZE)
    .equ Heap_Size, __HEAP_SIZE
#else
    .equ    Heap_Size, 8192
#endif
    .globl __HeapBase
    .globl __HeapLimit
__HeapBase:
    .if Heap_Size
    .space Heap_Size
    .endif
    .size __HeapBase, . - __HeapBase
__HeapLimit:
    .size __HeapLimit, . - __HeapLimit

    .section .isr_vector
    .align 2
    .globl __isr_vector
__isr_vector:
    .long   __StackTop                  /* Top of Stack */
    .long   Reset_Handler
    .long   NMI_Handler
    .long   HardFault_Handler
    .long   MemoryManagement_Handler
    .long   BusFault_Handler
    .long   UsageFault_Handler
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   SVC_Handler
    .long   DebugMon_Handler
    .long   0                           /*Reserved */
    .long   PendSV_Handler
    .long   SysTick_Handler

  /* External Interrupts */
    .long   POWER_CLOCK_IRQHandler
    .long   RADIO_IRQHandler
    .long   UARTE0_UART0_IRQHandler
    .long   SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQHandler
    .long   SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQHandler
    .long   NFCT_IRQHandler
    .long   GPIOTE_IRQHandler
    .long   SAADC_IRQHandler
    .long   TIMER0_IRQHandler
    .long   TIMER1_IRQHandler
    .long   TIMER2_IRQHandler
    .long   RTC0_IRQHandler
    .long   TEMP_IRQHandler
    .long   RNG_IRQHandler
    .long   ECB_IRQHandler
    .long   CCM_AAR_IRQHandler
    .long   WDT_IRQHandler
    .long   RTC1_IRQHandler
    .long   QDEC_IRQHandler
    .long   COMP_LPCOMP_IRQHandler
    .long   SWI0_EGU0_IRQHandler
    .long   SWI1_EGU1_IRQHandler
    .long   SWI2_EGU2_IRQHandler
    .long   SWI3_EGU3_IRQHandler
    .long   SWI4_EGU4_IRQHandler
    .long   SWI5_EGU5_IRQHandler
    .long   TIMER3_IRQHandler
    .long   TIMER4_IRQHandler
    .long   PWM0_IRQHandler
    .long   PDM_IRQHandler
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   MWU_IRQHandler
    .long   PWM1_IRQHandler
    .long   PWM2_IRQHandler
    .long   SPIM2_SPIS2_SPI2_IRQHandler
    .long   RTC2_IRQHandler
    .long   I2S_IRQHandler
    .long   FPU_IRQHandler
    .long   USBD_IRQHandler
    .long   UARTE1_IRQHandler
    .long   QSPI_IRQHandler
    .long   CRYPTOCELL_IRQHandler
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   PWM3_IRQHandler
    .long   0                           /*Reserved */
    .long   SPIM3_IRQHandler
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */
    .long   0                           /*Reserved */

    .size __isr_vector, . - __isr_vector

/* Reset Handler */


    .text
    .thumb
    .thumb_func
    .align 1
    .globl Reset_Handler
    .type Reset_Handler, %function
Reset_Handler:


/* Loop to copy data from read only memory to RAM.
 * The ranges of copy from/to are specified by following symbols:
 *      __etext: LMA of start of the section to copy from. Usually end of text
 *      __data_start__: VMA of start of the section to copy to.
 *      __bss_start__: VMA of end of the section to copy to. Normally __data_end__ is used, but by using __bss_start__
 *                    the user can add their own initialized data section before BSS section with the INTERT AFTER command.
 *
 * All addresses must be aligned to 4 bytes boundary.
 */
    ldr r1, =__etext
    ldr r2, =__data_start__
    ldr r3, =__bss_start__

    subs r3, r2
    ble .L_loop1_done

.L_loop1:
    subs r3, #4
    ldr r0, [r1,r3]
    str r0, [r2,r3]
    bgt .L_loop1

.L_loop1_done:

/* This part of work usually is done in C library startup code. Otherwise,
 * define __STARTUP_CLEAR_BSS to enable it in this startup. This section
 * clears the RAM where BSS data is located.
 *
 * The BSS section is specified by following symbols
 *    __bss_start__: start of the BSS section.
 *    __bss_end__: end of the BSS section.
 *
 * All addresses must be aligned to 4 bytes boundary.
 */
#ifdef __STARTUP_CLEAR_BSS
    ldr r1, =__bss_start__
    ldr r2, =__bss_end__

    movs r0, 0

    subs r2, r1
    ble .L_loop3_done

.L_loop3:
    subs r2, #4
    str r0, [r1, r2]
    bgt .L_loop3

.L_loop3_done:
#endif /* __STARTUP_CLEAR_BSS */

/* Execute SystemInit function. */
    bl SystemInit

/* Call _start function provided by libraries.
 * If those libraries are not accessible, define __START as your entry point.
 */
#ifndef __START
#define __START _start
#endif
    bl __START

    .pool
    .size   Reset_Handler,.-Reset_Handler

    .section ".text"


/* Dummy Exception Handlers (infinite loops which can be modified) */

    .weak   NMI_Handler
    .type   NMI_Handler, %function
NMI_Handler:
    b       .
    .size   NMI_Handler, . - NMI_Handler


    .weak   HardFault_Handler
    .type   HardFault_Handler, %function
HardFault_Handler:
    b       .
    .size   HardFault_Handler, . - HardFault_Handler


    .weak   MemoryManagement_Handler
    .type   MemoryManagement_Handler, %function
MemoryManagement_Handler:
    b       .
    .size   MemoryManagement_Handler, . - MemoryManagement_Handler


    .weak   BusFault_Handler
    .type   BusFault_Handler, %function
BusFault_Handler:
    b       .
    .size   BusFault_Handler, . - BusFault_Handler


    .weak   UsageFault_Handler
    .type   UsageFault_Handler, %function
UsageFault_Handler:
    b       .
    .size   UsageFault_Handler, . - UsageFault_Handler


    .weak   SVC_Handler
    .type   SVC_Handler, %function
SVC_Handler:
    b       .
    .size   SVC_Handler, . - SVC_Handler


    .weak   DebugMon_Handler
    .type   DebugMon_Handler, %function
DebugMon_Handler:
    b       .
    .size   DebugMon_Handler, . - DebugMon_Handler


    .weak   PendSV_Handler
    .type   PendSV_Handler, %function
PendSV_Handler:
    b       .
    .size   PendSV_Handler, . - PendSV_Handler


    .weak   SysTick_Handler
    .type   SysTick_Handler, %function
SysTick_Handler:
    b       .
    .size   SysTick_Handler, . - SysTick_Handler


/* IRQ Handlers */

    .globl  Default_Handler
    .type   Default_Handler, %function
Default_Handler:
    b       .
    .size   Default_Handler, . - Default_Handler

    .macro  IRQ handler
    .weak   \handler
    .set    \handler, Default_Handler
    .endm

    IRQ  POWER_CLOCK_IRQHandler
    IRQ  RADIO_IRQHandler
    IRQ  UARTE0_UART0_IRQHandler
    IRQ  SPIM0_SPIS0_TWIM0_TWIS0_SPI0_TWI0_IRQHandler
    IRQ  SPIM1_SPIS1_TWIM1_TWIS1_SPI1_TWI1_IRQHandler
    IRQ  NFCT_IRQHandler
    IRQ  GPIOTE_IRQHandler
    IRQ  SAADC_IRQHandler
    IRQ  TIMER0_IRQHandler
    IRQ  TIMER1_IRQHandler
    IRQ  TIMER2_IRQHandler
    IRQ  RTC0_IRQHandler
    IRQ  TEMP_IRQHandler
    IRQ  RNG_IRQHandler
    IRQ  ECB_IRQHandler
    IRQ  CCM_AAR_IRQHandler
    IRQ  WDT_IRQHandler
    IRQ  RTC1_IRQHandler
    IRQ  QDEC_IRQHandler
    IRQ  COMP_LPCOMP_IRQHandler
    IRQ  SWI0_EGU0_IRQHandler
    IRQ  SWI1_EGU1_IRQHandler
    IRQ  SWI2_EGU2_IRQHandler
    IRQ  SWI3_EGU3_IRQHandler
    IRQ  SWI4_EGU4_IRQHandler
    IRQ  SWI5_EGU5_IRQHandler
    IRQ  TIMER3_IRQHandler
    IRQ  TIMER4_IRQHandler
    IRQ  PWM0_IRQHandler
    IRQ  PDM_IRQHandler
    IRQ  MWU_IRQHandler
    IRQ  PWM1_IRQHandler
    IRQ  PWM2_IRQHandler
    IRQ  SPIM2_SPIS2_SPI2_IRQHandler
    IRQ  RTC2_IRQHandler
    IRQ  I2S_IRQHandler
    IRQ  FPU_IRQHandler
    IRQ  USBD_IRQHandler
    IRQ  UARTE1_IRQHandler
    IRQ  QSPI_IRQHandler
    IRQ  CRYPTOCELL_IRQHandler
    IRQ  PWM3_IRQHandler
    IRQ  SPIM3_IRQHandler

  .end

[Edvin]

Hello,

When I add some debug console printing, the crash seems to happen a few moments AFTER setting the vector address. Is this interrupt related?

 What sort of Crash do you see? Does it print anything in the log? If it says something like "Fatal error.", can you try to add the define DEBUG to your preprocessor definitions? What does the log say then?

You say that nothing more is printed. Have you tried debugging?

When you try to debug your application with a bootloader present, you need to either perform the DFU, or to manually program something called bootloader settings. use the nrfutil command

nrfutil settings generate --help to see how to generate that. 

Then, when you debug, you need to not program anything. In ses it is possible to "Attach debugger". I don't know what IDE you are using, but see if you can find something similar. If you can't find it, please let me know what IDE you are using.

NB: We are really short staffed due to Summer Holidays in Norway. You must expect some extra delay in technical questions these days, I am afraid. I am sorry for the inconvenience.

BR,
Edvin

[theslawek]

Hi Edvin,

What sort of Crash do you see? Does it print anything in the log? If it says something like "Fatal error.", can you try to add the define DEBUG to your preprocessor definitions? What does the log say then?

Nothing besides what I already posted and I already have DEBUG flag set in the compiler.

You say that nothing more is printed. Have you tried debugging?

No, I haven't figured that out yet.

When you try to debug your application with a bootloader present, you need to either perform the DFU, or to manually program something called bootloader settings. use the nrfutil command

nrfutil settings generate --help to see how to generate that. 

Then, when you debug, you need to not program anything. In ses it is possible to "Attach debugger". I don't know what IDE you are using, but see if you can find something similar. If you can't find it, please let me know what IDE you are using.

My Makefile already makes the bootloader settings. I am using VSCode and I have a JLink. I could use something like Segger Ozone to debug, right? Any useful tutorials on this? I haven't found one.

Thanks for your help.

[Edvin]

Hello,

It is a bit tricky to debug while having a bootloader, but as long as you flash the bootloader settings file, it should be possible. Just make sure your IDE/debugger doesn't write anything to the nRF before it starts the debug session. In Segger Embedded Studio (which I can recommend) there is an option "attach debugger", which will do just that. Assume that the application is already flashed, and start a debug session. Ozone works in the same way (tested just now). If your main() function is not reached in Ozone, then either the bootloader has rejected the application (due to incorrect bootloader settings, probably), or you are missing something, like the bootloader or the softdevice (or MBR if your application doesn't use the softdevice). 

You say you are using the nRF52840 Dongle? Have you attached a debugger? Please note this guide, when using the dongle for development. There are some power registers and so that you need to take care of. It is easier to use an nRF52840 DK for development. It is made for it, while the dongle is actually just a helper tool for nRF Connect for Desktop and so on.

I assume you have already erased the pre-programmed bootloader that comes with the nRF52840 Dongle? But you also remembered to flash your own bootloader? Because if not, the ble_dfu_buttonless_async_svci_init() will fail.

BR,

Edvin