How to generate a Bootloader + Softdevice + Application zip for OTA updates/DFU.

[Mr Sunshine]

Hello,

For OTA updates or DFU I want to create a zip file that contains the Bootloader, Softdevice, and Application into one, But when I generate this through nrfutil.exe and update it with the nRF Toolbox I only see that the application is updating. When updating the screen of the application starts at 2/2, so I assume that the bootloader and softdevice are skipped.

For more information I use the nRF52832 chip and I use the SDK 15.0.0. version (which uses the s132_nrf52_6.0.0_softdevice). The code I use to generate the zip is:

nrfutil pkg generate new_DFU.zip --hw-version 52 --sd-req 0xA8 --sd-id 0xA8 --softdevice softdevice.hex --bootloader-version 0 --bootloader bootloader.hex --key-file key_node.pem --application-version 0 --application application.hex

What am I missing? What am I doing wrong?

[Hung Bui]

Hi, 

Which softdevice do you have on the device before the DFU update ? 

After the DFU update do you have the application running as it should and do you have the new softdevice be updated ? 

I am not aware of that the nRF Toolbox would skip DFU update for softdevice and bootloader. 

If you only create the SD+BL .zip package would the DFU update succeed ?

[Mr Sunshine]

Both softdevices are the same (s132_nrf52_6.0.0_softdevice.hex), the reason why I re-update it is to have use one zip that contains de bootloader and the application. 

After the DFU I only notice that the application is changed, while the bootloader stays on the old one. I can't say anything about the softdevice as I update it to the same version.

I don't see it updating on the screen, and I assume that the (1/2) indicator is for the bootloader/softdevice update. Unless the update is really fast in which I cannot see it.

haven't tested SD+BL.zip jet, I'll try that one.

[Mr Sunshine]

mrono said:

Unless you specifically configured it to allow downgrading.

Does downgrading also mean same version update? And how can I prevent this rejection, are there examples?

[Hung Bui]

Hi Sunshine, 

Case 1: You would need to dig deep into the bootloader to know how it works and modify it. It would require some work load but I think it's the best option for you if you want to have good user experience. We unfortunately don't have a guide for this task yet. But I believe it's not a blocker. 

Case 2: If you want better user experience Case 1 should be better. But can you make the disconnect and reconnect transparent to the customer ? Considering that it would happens very quickly and require no action from end customer, no indication that the device reset ? 

Case 3: It's very similar to Case 2. Same user experience so Case 1 should be better. I'm not very familiar with the flutter library so I can't really comment. 

All in all, to be able to achieve what you want, you may need to modify the bootloader and the DFU protocol to allow BL+APP update (even if you do SD+BL+APP there will still be 2 phases).

But please consider that normally it's not very often that you need to update the bootloader unless there is something special with your application that you need to update the bootloader often. If it doesn't happen so often I would think that end customer would be OK with a 2-phases update. 

[Mr Sunshine]

Hi Hung,

Hung Bui said:

But please consider that normally it's not very often that you need to update the bootloader unless there is something special with your application that you need to update the bootloader often.

Normally I only need to update the Application, but due to a issue in the writing space I had to alter something in the Bootloader. So in theory the bootlader only needs to be updated once.

About case 1 I'm not that experienced in altering the code in letting it allow the BL + APP zip update. I don't have the full grasp on how the DFU update proces works. So a guide or example would help.

Case 2 should be a better approach because the bootlader only need one update. I should communicate this with the application designer to see if the UI can guide the user in reconnecting with the nrf52832. If the bootloader is updated the user shouldn't have to undergo this proces again.

[Hung Bui]

If you are planning to do it only once I don't see the point of modifying the bootloader to support APP+BL. I would suggest to send 2 files or to modify the app to do 2 files in the background. 

[Mr Sunshine]

thank you for your time. I'll see what I can do.