Jump to bootloader (mcuboot) from application without button

RE: Jump to bootloader (mcuboot) from application without button

mlac — Mon, 01 Jul 2024 19:51:18 GMT

Thanks for the reference! This has been trivial to implement based on https://docs.zephyrproject.org/latest/services/retention/index.html

I used the featured devicetree fragments and Kconfig options.

RE: Jump to bootloader (mcuboot) from application without button

Vidar Berg — Tue, 18 Jun 2024 07:02:14 GMT

You can include the NRF POWER HAL with '#include <hal/nrf_power.h>' and use the gpregret _set()/_get functions.

I also noticed that we now have introduced this new method to enter serial recovery mode: https://github.com/nrfconnect/sdk-mcuboot/blob/6869a65c9171849f1c50407b924e875fcc9d6e92/boot/zephyr/Kconfig.serial_recovery#L167. You may want to check if this symbol is available in the SDK version you are working with. In that case, it may be worth using the Retention System to avoid having to patch the mcuboot code.

RE: Jump to bootloader (mcuboot) from application without button

mlac — Mon, 17 Jun 2024 13:48:05 GMT

Thanks, Vidar.

How can I read/write GPREGRET in Zephyr?

RE: Jump to bootloader (mcuboot) from application without button

Vidar Berg — Mon, 17 Jun 2024 08:58:31 GMT

Hi,

If you aren't using the Retention System for anything else, then I would just use the GPREGRET register directly. I don't see any benefit of using the retnetion system in that case.

RE: Jump to bootloader (mcuboot) from application without button

mlac — Sat, 15 Jun 2024 16:19:26 GMT

Hi guys,

I want to achieve the same as Michael.

What are the pros and cons of using GPREGRET vs the retention system, Vidar?

RE: Jump to bootloader (mcuboot) from application without button

Vidar Berg — Tue, 26 Mar 2024 12:39:53 GMT

Hello Michael,

It is currently not implemented, but you can use the the GPREGRET register like in the nRF5 SDK or use Retention System and have the application store a flag to signal the bootloader to enter serial recovery mode on next reboot.

You can trigger an NVIC_SystemReset() from the application by calling sys_reboot(0).

This is where serial recovery mode is entered when CONFIG_BOOT_SERIAL_WAIT_FOR_DFU is enabled:

https://github.com/nrfconnect/sdk-mcuboot/blob/86af2de75205ec5f2c846a2393934360de22fde4/boot/zephyr/main.c#L505

Best regards,

Vidar

RE: Jump to bootloader (mcuboot) from application without button

puz_md — Tue, 26 Mar 2024 12:13:58 GMT

Hello Vidar,

thanks for the fast reply. Waiting for DFU increases startup time, so we try to jump from the application into the bootloader under certain conditions. (This way, the bootloader entry could also be hidden or protected.) We used this concept in all our older products, as they are usually deployed in the field and it is not feasible to perform a power cycle for entering the bootloader.

If I understand correctly, there is no such feature for enabling recovery mode from the application yet? Are there any plans to implement it in the future?

As a dirty workaround, would it be possible to set a digital output pin in the application and then perform a reset (how can I perform a reset) and the bootloader reads the pin that I just set as a "pressed button"?

Best regards,

Michael

RE: Jump to bootloader (mcuboot) from application without button

Vidar Berg — Tue, 26 Mar 2024 12:05:38 GMT

Hello Michael,

I'm glad to hear that you enjoyed the DFU course!

[quote user=""]If I understand correctly, to enter the bootloader (for Serial Recovery), the bootloader button has to be activated during startup.[/quote]

Yes, you can use a button to signal the bootloader to enter Serial recovery on boot. Another option is to enable the CONFIG_BOOT_SERIAL_WAIT_FOR_DFU=y symbol in your bootloader build. This will make the bootloader always enter serial recovery on startup.

[quote user=""]Further, is the overlay that I created for my main project (board_name.overlay) also applied to the mcuboot child? Or will I have to create a separate overlay file for mcuboot (child_image\mcuboot.overlay)?[/quote]

Yes, you will need to create a separate overlay for the mcuboot build. You can do this by creating a child_image folder, as you mentioned. https://developer.nordicsemi.com/nRF_Connect_SDK/doc/2.6.0/nrf/config_and_build/multi_image.html#permanent-configuration-changes-to-child-images

Best regards,

Vidar