DFU: Error: Invalid object

[jfsaxberg]

We have created a Node project to be used on our backend in order to create a packet that can be downloaded on a mobile phone, then transferred to a device via DFU.

nrfutil pkg display works and gives me output, but when I transfer the zip file with nRF Connect it fails with "Invalid object".

Is there any way to validate the zip file and get some insight into what is wrong?

I assume the problem is with the signature.

I use protocol buffers just like nrfutil seems to do, but is there any detailed information on how to construct initpacket.dat?

Is it possible to use nrfutil verify?

github.com/.../signing.py

More details here:

github.com/.../3

[Hung Bui]

Hi, 

Invalid object can be the result of many different issues. Please take a look at nrf_dfu_req_handler.h file in the bootloader project. You can find this: 

NRF_DFU_RES_CODE_INVALID_OBJECT          = 0x05,    //!< Data object does not match the firmware and hardware requirements, the signature is wrong, or parsing the command failed.

You may want to test with the debug variant of the bootloader and step into the code to see what exactly throwing NRF_DFU_RES_CODE_INVALID_OBJECT out. 

You can verify the init packet with the signature your provide but there still a chance that your have something wrong on the DFU package that the bootloader find it's incorrect. 

[jfsaxberg]

I found the problem.

When using protocol buffers, the message to sign is prepended with 4 bytes which I presume is the length?

[Hung Bui]

Hi,

Glad to know that you got a solution. It's been a while that I haven't worked with the protobuf. My suggestion is to look at how the init packet be generated in nrfutil to compare to what you do: 

https://github.com/NordicSemiconductor/pc-nrfutil/blob/release/v6.1/nordicsemi/dfu/init_packet_pb.py