Secure DFU serial bootloader

RE: Secure DFU serial bootloader

Erwin v. H. — Tue, 16 Jul 2019 13:49:55 GMT

Hi,

I made a mistake on my side, the size of the Tx buffer was exact the same size as the expected MTU, I forgot to allocate a byte for the opcode.

Therefore the signature failed everytime after uploading the init packet

Regards,

Erwin

RE: Secure DFU serial bootloader

tesc — Tue, 02 Jul 2019 16:07:46 GMT

Hi,

So to be clear, the update package should be generated using the private key, and the bootloader is made using the corresponding public key.

While I am not familiar with HxD, the data should be sent in the same order it appears in the .dat file, which I presume is the same as what is displayed in any hex editor. (I.e. endianness is kept as written to file by nrfutil when generating the dfu package. / The binary data files in the zip are to be treated as a stream of bytes.)

In order to check that everything is OK with the generated .dat file for the particular firmware and key pair, have you done a test of the serial DFU using nrfutil as the DFU controller (host)? (Full description in the Secure DFU Bootloader over Serial Link (UART/USB) example documentation.)

You can have a look at the contents of the package with "nrfutil pkg display <name of zip file>", e.g. "nrfutil pkg display my_dfu_package.zip", to check if everything seems to be in order.

For a reference implementation you can have a look at the nrfutil source.

Regards,
Terje

RE: Secure DFU serial bootloader

Erwin v. H. — Fri, 28 Jun 2019 12:30:55 GMT

Dear,

Do you have any idea how i can continue.

As is said i currently always get a signature error after sending the init packet.

Do i have to search it in the method of sending or in a mismatch of signature/private key between the generated package and bootloader?

Regards,

Erwin

RE: Secure DFU serial bootloader

Erwin v. H. — Wed, 26 Jun 2019 14:54:50 GMT

The bootloader is based on SDK 15.3 and I generated the update package an public key with the same private key (nRF utility)

Regards,

Erwin

RE: Secure DFU serial bootloader

tesc — Wed, 26 Jun 2019 13:39:56 GMT

Hi,

What version of the DFU bootloader is on the DFU target, based on what version of the SDK?

How do you generate the DFU update package?

Are you using Secure DFU, and have you signed the update using the correct private key?

Regards,
Terje