SB2.1 Image Load from Code

[awseiger]

I am trying to implement a reliable bootloader system that utilizes the NXP SB2.1 image format. To do this, I need to be able to do the following:

1. Generate an SB2.1 image from the currently-executing program to be stored in off-chip SPI flash for ROM bootloader recovery

2. Decode an SB2.1 image stored in another section of SPI Flash and copy it to the boot space.

I cannot find a way to load an SB2.1 file into the ROM bootloader through anything but the blhost interface, and in my desired implementation I need to do this in software internal to the LPC55.

Is the code for generating/decoding an SB2.1 file available? If so I can write our bootloader code to encode/decode these files.

Thank you!

[awseiger]

Is there a better explanation of the SB2.1 format? AN12283 does not have a detailed description of the format and how it works.

Also, is there a way to access the SB2.1 firmware load commands via the same interface the ROM-Based flash driver uses? 

Thank you!

[ZhangJennie]

Hi

SB2.1 file is sign+encrypted image generated by elftosb from plain image. This is a boot images supported by LPC55Sxx.We must use it with secure boot via ISP.

We can’t decode it and program with source code.

If you want to program flash inside source code, please use plain image directly.

For more about sb2.1 file and secure boot, see AN12283.

Have a nice day

Jun Zhang