RE: DFU from internal RAM nRF52840

Einar Thorsrud — Fri, 28 Apr 2023 12:18:27 GMT

Hi,

[quote user=""]1. Is there any example where I can DFU from RAM?[/quote]

If I understand you correctly, you want to store the entire new image in flash (so that it acts like a temporary secondary slot)? If so, we do not have any bootloader or DFU solution that supports that, and it does not seem like a good idea. I do not know which SDK you are using, but for both SDK's we provide, activation of the image happens after performing a reset into the bootloader. And the RAM content cannot be guaranteed during a reset. Moreover, if something happens during activation, then you could end up in a situation where you have deleted the old application and started to copy in the new one, but not completed it. Normally, the bootloader would detect this upton the next reset and continue to copy the new image in place. However, if it was in RAM it might be corrupted or lost.

[quote user=""]2. Is it possible to be DFU per blocks of data? or I need to have the complete FW on the RAM and then DFU?[/quote]

You need to have the whole new FW. You need a working application to transfer the image, and so you need to transfer the whole image before you activate it.

Note that is your device is flash constrained and option can be to put the secondary slot on external flash (See Using external flash memory partitions if using the nRF Connect SDK).