Zephyr nrf connect application will not start without JFlash F9 command

[BvdP4Celsius]

Hi,

A have an application on a custom board that will not start, unless I use JFlash Start Application command, or attache the debugger.
I already added CONFIG_BOARD_ENABLE_DCDC=n after reading https://devzone.nordicsemi.com/f/nordic-q-a/77570/zephyr-project-on-a-custom-board-wont-start-up-after-removing-debugger

Any other tricks?

[Simonr]

Hi

Does your custom board have an external 32.768 kHz LF crystal on the design? If not, that might be related to the issue you're having, and you'll have to make sure that the internal RC oscillator is configured instead of the external LF crystal.

It should be sufficient to make sure that CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n and CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y. For reference: https://github.com/nrfconnect/sdk-zephyr/blob/main/drivers/clock_control/Kconfig.nrf#L29-L55 

Best regards,

Simon

[BvdP4Celsius]

Hi Simon,

The xtal is mounted:

It seems to be related to the CONFIG_BOOTLOADER_MCUBOOT=y setting. When I build without this setting, the application will start as soon as powered.

[Simonr]

And it runs without any errors what so ever in debug mode, but fails/doesn't start in release mode? What exactly does your bootloader do in your application? The config sets several required build systems and device tree options in order for the image generated to be bootable using the MCUBoot open source bootloader. Currently, this includes:

• Setting ROM_START_OFFSET to a default value allowing space for the MCUBoot image header
• Activating SW_VECTOR_RELAY_CLIENT on Cortex-M0 targets with no built-in vector relocation mechanisms.

By default, this option instructs Zephyr to initialize the core architecture HW registers during boot, as long as it's supported by the application. 

Best regards,

Simon

[BvdP4Celsius]

Hi Simon,

As mentioned before, the bootloader is doening not much except starting the image in slot 1. 
I notice that starting the ozone debugger as mentioned by Edvin  here requires a double 'run' command.
The system halts in syscall.h twice before starting my application. (in the 'Indicate whether the CPU is currently in user mode'part.
Does this help you to point out what I missed?

[Simonr]

Hi

It did not, but discussing with a colleague had a tip. Have you set CONFIG_BOARD_ENABLE_DCDC=n in the bootloader build as well? Sorry I missed this initially.

Best regards,

Simon