bootloader project in nCS

[Ubaid_M]

Hi,

1. Is bootloader file and firmware file, different for projects build on nCS..?
    Or a single executable build file consists both bootloader & firmware..?

2. Can you suggest a sample program to build a bootloader project..?

Thanks,

[Edvin]

Hello,

Ubaid_M said:

1. How does how does the image boot if I have not enabled CONFIG_BOOTLOADER_MCUBOOT=y..?

Then there is no bootloader. The application will be located at 0x00.

Ubaid_M said:

Some preexisting bootloader does the job or if system does not find anything at the address,

no. See 1.

Ubaid_M said:

3. Can you please suggest if this "BOOTLOADER_MCUBOOT" checks for firmware file image code signing before booting the image..?

Yes it does.

Ubaid_M said:

4. If it does, how does it use the key for code signing check on the firmware file..?

It uses a default key, which you should see when you compile. Some message saying that this is a default key which should not be used for production, and that you should change it.

Ubaid_M said:

5. How can I update this key..?

I believe it says in the same warning.

Best regards,

Edvin

[Ubaid_M]

Thank you Edvin,

Edvin said:

Then there is no bootloader. The application will be located at 0x00.

It is clearer now.

Now if I want to generate a private key and add it into the MCUBOOT, what process do I follow..?

Please suggest.

Thanks

[Edvin]

Please see this link on how to generate new key pairs.

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/tfm/docs/technical_references/design_docs/tfm_secure_boot.html#second-stage-bootloader-in-tf-m

There is also a Kconfig definition

CONFIG_BOOT_SIGNATURE_KEY_FILE (described as "config BOOT_SIGNATURE_KEY_FILE" in NCS\nrf\modules\mcuboot\Kconfig) where you can set the absolute path of the key file that you have generated.

Best regards,

Edvin

[Ubaid_M]

Hello Edvin,

Edvin said:

CONFIG_BOOT_SIGNATURE_KEY_FILE

Thank you for the suggestion, it helps.

Further, I understand the usual way mcuboot works with SLOT-0, SLOT-1 & SCRATCH memory locations towards swapping of images for firmware update.

I want to customize a few things here,

1. I want to map SLOT-1 & SCRATCH memory locations to external serial flash locations.

2. I want to provide mcuboot SPI interface APIs to interact with external flash.

So, for the above 2 requirements, kindly suggest how and where I can tweak & build the mcuboot source code.

If any sample is available wherein mcuboot source code is modified, it would be great.

Thanks,

Ubaid

[Edvin]

Ubaid_M said:

1. I want to map SLOT-1 & SCRATCH memory locations to external serial flash locations.

2. I want to provide mcuboot SPI interface APIs to interact with external flash.

What chip are you using? I believe it is possible to offload this to an external QSPI flash chip by using CONFIG_NORDIC_QSPI_NOR=y. Without knowing the details, perhaps you can look into what this does, and try to implement something similar using SPI. 

The MCUBOOT bootloader project is located in ncs <vX.Y.Z>\bootloader\mcuboot.

BR,
Edvin