DFU Upgrade of only Bootloader (not SoftDevice)

RE: DFU Upgrade of only Bootloader (not SoftDevice)

emb_dev — Wed, 02 Mar 2022 15:08:00 GMT

Hi, thanks for the quick reply!

I will try the unpack and repack approach as well.

If that doesn't work, your hack to nrfutil looks promising!

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Wed, 02 Mar 2022 13:04:26 GMT

Hi, I have posted more information in another ticket:

https://devzone.nordicsemi.com/f/nordic-q-a/84879/feature-request-please-allow-app-bl-dfu-upgrades-in-nrfutil

In the mean time I have also hacked nrfutil to be able to create APP+BL packages, it was surprisingly easy. See https://github.com/NordicSemiconductor/pc-nrfutil/pull/371

I actually use my own tool "nrfdfu" (https://github.com/infsoft-locaware/nrfdfu) for the upgrade, but I also tried nrfutil before. Has been a long time since I tried with the Android app, sorry.

I did not change the manifest file and I unpacked and repacked the .zip file under Linux.

Hope that helps

RE: DFU Upgrade of only Bootloader (not SoftDevice)

emb_dev — Wed, 02 Mar 2022 12:44:14 GMT

Hi Bruno Randolf,

I am facing a similar task where I need a BL+APP OTA DFU and was happy to find your post. I tried the approach you described and packed the BL only .dat and .bin into the .zip package with APP+SD+BL and renamed them. But using the nrfConnect app on an Android phone, the Device got disconnected after the BL update and the phone was stuck within the DFU process.

Did you change the manifest.json file in the .zip file? Did you unpack the .zip file and repacked it or did the manipulation with a tool like 7-zip n the packed state?

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Mon, 24 May 2021 10:47:28 GMT

Just for reference I was able to manually create a APP+BL DFU package by manipulating the ZIP files and copying the .bin and .dat file from a BL only package to a APP+SD+BL package as sd_bl.bin and sd_bl.dat. Then repacked the ZIP and it now contains APP+BL. The tools (nrfutil and github.com/.../nrfdfu) don't have a problem updating this.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Fri, 21 May 2021 12:29:26 GMT

Exactly, it wouldn't affect the bootloader at all, just the surrounding tools. As devices with smaller flash like the 52810 are available, where SD upgrades are not feasible, I think this feature gets more important.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Einar Thorsrud — Fri, 21 May 2021 10:01:12 GMT

I am not sure why that decision was made, but most likely it was because it did not seem like a important feature, and keeping the BL as small as possible is a priority. Note that actually, BL+SD+APP is also not supported by the bootloader directly, but by the surrounding tools. Upgrade is in fact split in two there as well, even though it is in a single .zip package.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Fri, 21 May 2021 09:08:53 GMT

Why is this not supported? As far as I can see it is exactly the same as a BL+SD update followed by a APP update, only without the SD.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Einar Thorsrud — Fri, 21 May 2021 09:06:25 GMT

I see. APP+BL is not supported though, and not possible. If you are making a app for your end customers to use in the field you could integrate this so that the operation looks like a single operation from the GUI user perspective, though.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Fri, 21 May 2021 07:54:04 GMT

Yes, unfortunately...

Another issue is the upgrade of APP+BL: That would be really useful to upgrade older versions. It should work the same way as APP+SD+BL updates, just without SD. The BL is updated first and then the application in one go. If we have to update BL first and then reconnect to MAC address + 1 to separately upgrade the APP that gets unmanageable really quickly if you have many devices in an environment.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Einar Thorsrud — Thu, 20 May 2021 13:27:53 GMT

I see. Then I suspect the only remaining option is to access the SWD pins and program using a debugger, though that may not be a real option for devices in the field.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Thu, 20 May 2021 07:55:52 GMT

Thank you - That's a very good idea! My bootloader supports button pin 16, GPREGRET and buttonless. But unfortunately P0.16 is not accessible from the outside.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Einar Thorsrud — Wed, 19 May 2021 15:16:04 GMT

Hi,

I see. The primary issue here is entering DFU mode without the WDT resetting the bootloader, then. One obvious possibility comes to mind, though it might not be possible. Which methods does the bootloader support for entering DFU mode? I ask because after a WDT reset, the WDT is also reset, i.e. it is disabled. So if you can start the bootloader immediately after a WDT reset without the app running first (and enabling the WDT), that could be a workaround. For instance if you have a button or pin that can be asserted during bootup to enter DFU mode?

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Wed, 19 May 2021 14:23:41 GMT

Thank you for your answer!

I use an adapted version of the secure bootloader from the SDK, but I have introduced a bug when WDT is activated by the application. The current application uses WDT so the bootloader crashes every time I enter it. So there is no way to update neither APP or BL. I think this case is hopeless...

I use the BLE transport. The flash layout is single bank and there is not enough space on nRF52810 to update the BL+SD...

I wonder why the bootloader + application combination is not allowed, as that would help in this case, when I upgrade older versions. As you said I have to update BL first and then the application, but it would be good to be able to do that in a single command as with APP+SD+BL upgrades.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Einar Thorsrud — Wed, 19 May 2021 12:05:38 GMT

Hi,

I have a few questions in order to understand more:

What bootloader have you flashed on the device and what changes have you made?
Which transport do you use (BLE or UART)?
What does your flash layout look like?

Generally, there is no problem upgrading just the bootloader without upbraiding the SoftDevice, as long as the new bootloader is built for the same SoftDevice. However, in order to support bootloader updates you must have enough free space in the application are to temporarily store the bootloader, and you must have a MBR params page. If either of these two are missing, bootloader update is not possible.

nrfutil does allow generating a upgrade image of the bootloader only, and that is also supported by the nrF5 SDK bootloader. The only combination that is not allowed is bootloader + application, so in this case you need to use two separate upgrade images and to one after the other.

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Wed, 19 May 2021 11:54:13 GMT

actually this is not an issue where anyone could help, so please ignore or delete this ticket

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Wed, 19 May 2021 11:35:29 GMT

actually the problem is that in the current state I can not do any upgrades at all

RE: DFU Upgrade of only Bootloader (not SoftDevice)

Bruno Randolf — Wed, 19 May 2021 11:28:35 GMT

Okay sorry, I see BL only updates are possible, but why not BL+APP