RE: Inconsistent settings CRC with nrfutil settings generate command

manu — Tue, 01 Oct 2024 14:02:15 GMT

Thanks for the quick response and explanation! This clears things for me.

RE: Inconsistent settings CRC with nrfutil settings generate command

Vidar Berg — Tue, 01 Oct 2024 13:56:24 GMT

Hi,

Thanks. I see you are using signature validation (ECDSA), not CRC. The signature will change with every iteration because it is computed using a random nonce. If you want the boot validation to remain the same you need to use HASH or CRC validation.

Best regards,

Vidar

RE: Inconsistent settings CRC with nrfutil settings generate command

manu — Tue, 01 Oct 2024 13:51:58 GMT

Hi,

Thanks for the response.

I create the settings file twice with:

nrfutil settings generate --family NRF52 --application myhex.hex --application-version-string "0.0.0" --app-boot-validation "VALIDATE_ECDSA_P256_SHA256" --key-file ecckey.txt --bootloader-version 0 --bl-settings-version 2 settings.hex

Then with settings display first time:

> nrfutil settings display settings.hex

Bootloader DFU Settings:
* File:                     settings.hex
* Family:                   nRF52
* Start Address:            0x0007E000
* CRC:                      0x8E686380
* Settings Version:         0x00000002 (2)
* App Version:              0x00000000 (0)
* Bootloader Version:       0x00000000 (0)
* Bank Layout:              0x00000000
* Current Bank:             0x00000000
* Application Size:         0x00041B14 (269076 bytes)
* Application CRC:          0xB1F669C0
* Bank0 Bank Code:          0x00000001
* Softdevice Size:          0x00000000 (0 bytes)
* Boot Validation CRC:      0xA22B4410
* SD Boot Validation Type: 0x00000000 (0)
* App Boot Validation Type: 0x00000003 (3)

Second time:

Bootloader DFU Settings:
* File:                     settings.hex
* Family:                   nRF52
* Start Address:            0x0007E000
* CRC:                      0x8E686380
* Settings Version:         0x00000002 (2)
* App Version:              0x00000000 (0)
* Bootloader Version:       0x00000000 (0)
* Bank Layout:              0x00000000
* Current Bank:             0x00000000
* Application Size:         0x00041B14 (269076 bytes)
* Application CRC:          0xB1F669C0
* Bank0 Bank Code:          0x00000001
* Softdevice Size:          0x00000000 (0 bytes)
* Boot Validation CRC:      0x732C0C40
* SD Boot Validation Type: 0x00000000 (0)
* App Boot Validation Type: 0x00000003 (3)

nruftil version is 7.7.0. Each time Boot Validation CRC changes. Each time, settings.hex file ends up with a new checksum so everytimewhen we combine identical bootloader and application binaries using mergehex the end result has a different checksum compared to previous run.

RE: Inconsistent settings CRC with nrfutil settings generate command

Vidar Berg — Tue, 01 Oct 2024 13:39:17 GMT

Hello,

The CRC should not change if you use the same input hex file each time. Could you please run 'nrfutil settings display settings.hex' and post the output here?

Thanks,

Vidar