RE: Application partly unresponsive after dual-bank DFU update

GPL — Sat, 29 May 2021 11:04:12 GMT

Hello Hung,

Thank you for your response.

I had some trouble recreating this issue as I didn't have access to the binary that caused the issue at first because it was tested on an external location. So I tried it at home with binaries of the same size & even larger. It turns out then everything works okay. And now that I understand the dual bank process better, the insufficient resources error also makes sense.

I first flashed the SD and BL, then via DFU uploaded the smaller binary. Confirmed it was working and then update with the bigger binary, causing the issues. If I update to the bigger binary right away (so no previous application present) it also does not work fully. I tried compiling the binaries myself (the others were compiled on an external environment) and everything works okay!

So I guess something else went wrong caused by the other compilation process. Sorry, I should have done more research first.

Thank you for your time!

RE: Application partly unresponsive after dual-bank DFU update

Hung Bui — Thu, 27 May 2021 14:13:26 GMT

Hi Gijs,

Please correct me if I'm wrong. What you tested was:

- You flashed the nRF52840 with SD+BL+APP A (App A is relatively small in size)

- You did DFU to update to APP B (App B has larger size 380kB as you mentioned)

- The application B only work partly.

- You tried to update APP B again but got InsufficientResources error.

If that's the case what we can suggest you to try is:

- Try to test SD+ BL (no application) and do DFU for APP B. Check if APP B works as it should. Try to read hex dump from the chip (nrfjprog.exe --readcode)

- Repeat your initial step, after you update APP B and it works partially, try to read a hex dump and compare it with the hex at step 1. You can use Notepad++ to compare 2 hex files.

You are correct about that if you force dual bank DFU update, the swap bank need to have enough space to receive the new image. This mean your application shouldn't be bigger than 50% of Bank 0+1 if you want to do another DFU update.

It's quite strange that the application only works partly, I suspect that the error may related to that you have a bootloader and it may change the behavior of the app (it shouldn't)