NRF52840 PDK BLE Secure DFU Bootloader

[nahro]

files.rar

Hello, I am using nRF5 SDK14.1.0 and soft device s140_nrf52840_5.0.0-2.alph.I can program the board witt the bootloader(both pca10056 and pca10056_debug) successfully and its advertising. I generated firmware package from the application hex file for both (both pca10056 and pca10056_debug) and i am using nRF Toolbox to update the firmware. Here is the steps that i followed:

1. program soft device.
2. program Bootloader (i am using iar and followed this) .
3. generate keys.
4. generate firmware package with and without bootloader settings page, and for both bootloader versions. DfuTarg start advertising and led1 and led3 is on, when i send the firmware package from nRF Toolbox led1 truns off and led2 truns on for 2 seconds and then DfuTarg start advertising again with led1 and led3 on, so there is no application running it's just a bootloader again!

[Hung Bui]

Hi Nahro,

It's not clear how you build the bootloader, have you generated your private and public keys and update the bootloader project with your own public key ?

Please follow my guide here.

[nahro]

Hi Hung, Yes i did, and i overwrite dfu public_key.c in the project with the public key that i got from the key file that i used for creating firmware package.

[Hung Bui]

Hi Nahro,

Could you check and send us:

• The log on the phone (you can swipe right on the phone to see the log when in nrfConnect, or install nRFLog app)

• The log on the bootloader, you need to enable either RTT or UART log

• The sniffer trace of the DFU process if you have a sniffer

[nahro]

Hi Hung, I debugged the bootloader and it failed in nrf_crypto_ecdsa_verify_hash() function which return 11

[nahro]

I think its a bug in the SDK because it verfiy the signature but return internal error! so i commented return NRF_DFU_RES_CODE_INVALID_OBJECT; and every thing works.

err_code = nrf_crypto_ecdsa_verify_hash(sig_info_p256, &crypto_key_pk, &init_packet_hash, &crypto_sig); if (err_code != NRF_SUCCESS) { NRF_LOG_ERROR("Signature failed"); //return NRF_DFU_RES_CODE_INVALID_OBJECT; }