Update process in FLASH memory (BANK1 to BANK0) from application

[Xav]

Hi,

We use the nRF51 (nRF51822) on our products with the S130 SDK 2.0.1. In order to update the BLE application that we developed, we use the bootloader (secure bootloader DFU : SDK 12.2.0). Currently the update is done via the BLE in DFU mode.

We now want to be able to update the Nordic application via the UART TTL link with our communication protocol that we have integrated into our application. The update would be done via the application by loading the new firmware in the memory area BANK1. Once loading is complete and checked, we would like to reboot on the bootloader (secure bootloader DFU) by indicating that an update is to make from the BANK1 to the BANK0.

Would you have already implemented update process? Do you have any examples that come close to this principle? Which libraries are needed to do that? How to tell the bootloader that an update is to be done (registry, ...)?

Regards,

[Hung Bui]

Hi Xavier, 

What you described is similar to the background DFU that we implemented in our IOT libraries. 

It's not implemented in SDK v12.x but it should be possible to follow what we did in newer SDK. Basically, you need to do something similar to nrf_dfu_postvalidate() function, where we write to the bootloader setting to bank 1 as NRF_DFU_BANK_VALID_APP. After the setting is written in flash, we will trigger a reset. When the bootloader boot up, it will check the setting and then swap the image when bank 1 is valid app. You can find the code doing that in nrf_dfu_continue() the call for it is inside nrf_dfu_init().

So what you do in the application is to receive image and then write to the bootloader setting as described then trigger a reset. 

[Xav]

Hi Hung,

Thanks for your answer. Could you send me a link to download this sample code?

Regards,

[Hung Bui]

You can have a look here: https://infocenter.nordicsemi.com/topic/sdk_nrf5_v16.0.0/iot_sdk_app_tftp_dfu.html?cp=6_1_4_2_4_9_2

The example is located at \examples\iot\tftp\background_dfu in SDK v16. 

Vidar has made an example for UART background DFU, it could be more simple. See here: https://devzone.nordicsemi.com/f/nordic-q-a/46336/bootloader-no-transport-dual-bank-dfu-and-dependencies

[Xav]

Thanks for your answer.

I am trying with this example.

Just a question. With DFU process in BLE communication, the file downloaded is the zip file.

In bank1, is it only the bin file that is downloaded ?

Regards,

[Hung Bui]

The data transfer via BLE is actually the binary image. The  DFU master's job (the phone) is to unzip it and get the init packet, binary image and send to the bootloader.