switch uECC bootloader to oberon via DFU?

RE: switch uECC bootloader to oberon via DFU?

Hieu — Thu, 08 Jun 2023 19:30:38 GMT

Hi Patrick,

Note: I just deleted an answer I posted ~10 minutes ago which contain incorrect information. The correct information is here:

It has been a very long time since my last reply. My sincerest apology for the wait.

I looked into it and here are the conclusions:

Changing the crypto backend to Oberon will always result in a bigger size than uECC. It is to the extent that the size of the bootloader will be too big to fit into the bootloader region.
The default size is documented in the Memory Layout section of the Bootloader doc.

Therefore, if you change into the Oberon crypto backend, the memory layout, including the start address of the bootloader must be changed. This means that during the upgrade, there is a window of time during the DFU process where the data where the MBR expects the bootloader reset handler to be is overwritten/not correct.

This is very risky when done on an in-field product, because a flash write failure or power failure can brick the device.

Therefore, I don't really recommend changing the crypto backend to Oberon. The benefit is not worth this risk.

I hope that is alright, since uECC is working for you now.

Once again, I am very sorry about the long wait and the (deleted) wrong answer.

Hieu

RE: switch uECC bootloader to oberon via DFU?

Hieu — Tue, 09 May 2023 14:29:27 GMT

Hi Patrick,

My apology for the long wait. Please know that I am still around. However, I am still recovering from the high loading time and still haven't been able to look into it yet. There is a holiday here next week, so it will be another high loading wave and some days off, but I will try to get to this as soon as I can.

Hieu

RE: switch uECC bootloader to oberon via DFU?

patjshan — Fri, 28 Apr 2023 16:44:38 GMT

No Problem! in the meantime I have found the compiled uECC library files that the original bootloader was compiled with, and I have recompiled a new bootloader with these files in the nrf5 17.1.0 SDK and the new softdevice and application code, so this is no longer a pressing issue. I am however still curious if for whatever reason the in the future we need to make changes to the bootloader whether or not this type of update would be possible.

RE: switch uECC bootloader to oberon via DFU?

Hieu — Fri, 28 Apr 2023 13:37:17 GMT

Hi Patrick,

I am unfamiliar with DFU across SDK versions. I will need to read about it, and most likely need to seek some internal help as well.

I hope you can wait for a few days. On top of the time necessary, my team is facing high loading due to some unavailability, and there is one holiday here on Monday next week.

My apology for the inconvenience.

Hieu

RE: switch uECC bootloader to oberon via DFU?

patjshan — Thu, 27 Apr 2023 17:27:41 GMT

Hello,

this is the response I get in nrf connect for desktop when I try to upload the OTA package containing the new softdevice and bootloader pair.

2023-04-27T16:41:09.355Z ERROR DFU failed with error: When writing 'EXECUTE' command to Control Point Characteristic of DFU Target: Operation code 4 (EXECUTE) failed on DFU Target. Result code 4 (INSUFFICIENT_RESOURCES).

the memory layout on the existing application is based on SDK 15.3.0 ble_app_buttonless example, and adjusted according to a devzone post that I can't find right now but basically it said that the reserved_flash section needed to be shifted by 4kB in 15.3.0 so thats been done. I have the MBR, then the s132 softdevice ver 6.1.1, than my application code (about 100kB) then FDS data, then the bootloader and bootloader settings pages. beow is the example of what my flash placement file looks like

<ProgramSection load="no" name=".reserved_flash" start="$(FLASH_PH_START) + 0x1000" size="$(FLASH_START)-$(FLASH_PH_START) - 0x1000" />

The bootloader in the current application was compiled with uECC library but I'm having difficulty rebuilding the library on my new machine due to network security issues. Thus I am interested in recompiling a new bootloader with the Oberon library and also in moving to the latest nrf5 sdk 17.1.0 and ver 7.2.0 of the softdevice. I have a full image of the firmware compiled n the 17.1.0 SDK that runs fine when all flashed to the chip together and 17.1.0 bootloader is flashed it can perform an OTA (I uploaded the same-version application code via OTA to it and it went through). Now I just need to figure out what order of updates need to be made to take my existing application code that uses the s132 ver 6.1.1 and bootloader with uECC library and eventually end up with the s132 ver 7.2.0, the application code that is compatible with the new version of softdevice, and the bootloader based on the Oberon library.

RE: switch uECC bootloader to oberon via DFU?

Hieu — Thu, 20 Apr 2023 13:34:18 GMT

Hi patjshan,

Do you have:

- The memory layout is in your existing devices?
- The start address and size of the application and bootloader on the existing devices?
- The start address and size of the new bootloader built with the Oberon library?

Could you please confirm if the DFU process failed with NRF_DFU_RES_CODE_INSUFFICIENT_RESOURCES at the Create Request step?

Hieu