Application Images with MCUboot (mcuboot_opensource)

[Bhumika18]

Hello,

I am currently working with the mcuboot_opensource bootloader example from the NXP SDK on an i.MX RT device. After successfully flashing the MCUboot bootloader, I would like to understand the correct process for flashing the application binary.

I have a few questions regarding this:

1. After programming the mcuboot_opensource bootloader, how should the application binary be flashed?

   • Which tool is typically used (e.g., MCUXpresso IDE, blhost, or other tools)?

   • Should the application be flashed directly to the primary slot address defined in the flash layout?

2. How do we sign the application image?

   • Is the signing process done using the imgtool utility?

   • What is the correct command or procedure to generate a signed binary image?

3. Is image signing mandatory?

   • Will MCUboot boot an unsigned image, or is signing always required?

   • Is there a way to disable signature verification for testing purposes?

I would appreciate any guidance on the correct workflow for flashing and signing application images when using MCUboot in a real project.

Thank you.

[Gavin_Jia]

Hi @Bhumika18 ,

Thanks for your interest in NXP MIMXRT series!

A1: Which tool is typically used?

Support is provided for IDE, JLink, or other debuggers, as well as for using blhost in serial download mode. The sole purpose is to write the signed image to the designated flash partition. 

• Should the application be flashed directly to the primary slot address defined in the flash layout?

>> Yes, we need to sign the image as described in the ReadMe before that.

A2: 

• Is the signing process done using the imgtool utility?

>> Yes, use imgtool. Use the tool included in the SDK rather than the one installed via pip to avoid any issues caused by version mismatches.

• What is the correct command or procedure to generate a signed binary image?

>> Please refer to the signing commands provided in the ReadMe.

A3:

• Will MCUboot boot an unsigned image, or is signing always required?

>> Signing is required by default.

• Is there a way to disable signature verification for testing purposes?

>> Customization requires the customer to thoroughly review the mcuboot_opensource project. I suspect it may provide the relevant configuration options.

Best regards,
Gavin