Generating binaries on vscode with prepended zeroed header to the image

[Ubaid_M]

Hello ,

I am using nrf Connect SDK v1.9.1 with nRF Connect extension for my application development.

With reference to the nordic documentation : https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/mcuboot/imgtool.html#incorporating-the-public-key-into-the-code:~:text=Zephyr%20build%20system%20will%20already%20prepended%20a%20zeroed%20header%20to%20the%20image

Please find as in below snap the binaries generated from vscode and nCS I am using, There is no padded zeroed header to my build binaries at 0x000000 (Right image below)

While the left image below is the binary i generated with just zephyr and no nCS. It clearly has zero padded header.

So my question is, How can I have zero padded header to binaries generated out of nCS..?
Can i use any config..?

Thanks,

Ubaid

[Sigurd Hellesvik]

Hi Ubaid,

I will look into this and return with more information tomorrow.

Regards,
Sigurd Hellesvik

[Ubaid_M]

Sigurd Hellesvik said:

I will look into this and return with more information tomorrow.

Yes please, 

Thanks

[Ubaid_M]

Hello Sigurd Hellesvik,

Sigurd Hellesvik said:

Aha, so you want to get the Zero padding.

Yes, This is what I need.

Sigurd Hellesvik said:

Do you build with MCUboot for both projects?
Do you see the same issue if you build without MCUboot for both projects?

Yes, I tried without mcuboot configured build and found that still generated binaries do not have zero prepended.

Thanks,

[Sigurd Hellesvik]

Hi,

I realize that you will need a bootloader if you offset the image in flash, as the chip will start at address 0x0000.

If you enable MCUboot in an nRF Connect SDK project, the address off zephyr.hex will be offset:

Here is a sample from zephyr.hex in the hello_world sample with CONFIG_BOOTLOADER_MCUBOOT=y:

Does this help?

Regards,
Sigurd Hellesvik

[Ubaid_M]

Hello Sigurd Hellesvik,

So now how will I achieve this on my bin files..?

Sigurd Hellesvik said:

Aha, so you want to get the Zero padding.

Thanks

[Sigurd Hellesvik]

From the same hello_world sample mentioned below, I take build/zephyr/zephyr.bin and convert it to hex using bin2hex.py.

bin2hex.py zephyr.bin converted_zephyr.hex

The resulting hex-file also has this padding:

converted_zephyr.hex

Regards,
Sigurd Hellesvik

[Ubaid_M]

Hello Sigurd,

Sorry, there seems to have been some miscommunication.

2 cases:

1. With the attached image, If image starts at 0x000210 address in memory, you can see the on LHS image that from address 0x00000 up until 000210 there is zeros prepended.! 

2. Whereas same image, when built with nCS on vscode, starts with 000000, straight away with data without no prepended zeros. Now I assume linker scripts may copy this at appropriate memory location as it is working.

But my problem is, how do I generate binary as in the first case using nCS VScode..?

Thanks,

[Sigurd Hellesvik]

Are you looking for CONFIG_FLASH_LOAD_OFFSET?

Regards,
Sigurd Hellesvik

[Ubaid_M]

Can I set CONFIG_FLASH_LOAD_OFFSET and my binary will look like LHS binary above?

[Sigurd Hellesvik]

I think it could be, but I am not 100% certain.

But I suggest that you give it a try on a development device.

Regards,
Sigurd Hellesvik

[Ubaid_M]

Sure will try, Thanks

So It will look like CONFIG_FLASH_LOAD_OFFSET=0x00
Or
CONFIG_FLASH_LOAD_OFFSET=0x200
..?

[Ubaid_M]

Hello Sigurd Hellesvik,

Can you please suggest on use of CONFIG_FLASH_LOAD_OFFSET