OTA DFU to custom memory address

RE: OTA DFU to custom memory address

senneverhaegen — Wed, 27 Apr 2022 15:32:26 GMT

I'm currently looking where I can modify the dfu process.

Unfortunately the alternative approach you suggested is not possible for me.

RE: OTA DFU to custom memory address

Vidar Berg — Wed, 27 Apr 2022 11:31:55 GMT

It is possible, but you would also need to modify the dfu process in your bootloader to place a new app images at 0x40000 instead of the default app start address (0x26000 for this particular version).

Edit: another alternative to modifying the dfu process is to always update the 2 application together. I.e. simply merge app hex "1" and "2", then create the app update package from that one hex file. You will still need a mechanism to tell the bootloader which reset handler it needs to branch to on boot, but I guess maybe you have a solution for that already.

RE: OTA DFU to custom memory address

senneverhaegen — Wed, 27 Apr 2022 11:15:36 GMT

Hi, thank you for your response.

I did modify the bootloader to launch the app at an address of my choosing (according to another article on this forum). I verified that it works, however, only if programmed with nrfjprog.

So given that I modified the bootloader correctly, is it still impossible using DFU?

RE: OTA DFU to custom memory address

Vidar Berg — Wed, 27 Apr 2022 11:09:55 GMT

Hi,

This is will not be possible with the original SDK bootloader, unfortunately. There is nothing in the DFU protocol which specify the app start address. It's always assumed to be right above the Softdevice.

[quote user=""]If I flash the program with nrfjprog, the application does go to 0x40000.[/quote]

Yes, the intelhex format includes address records telling nrjprog where store the data. But the Softdevice will still expect the application to start at 0x26000 unless the bootloader has configured the softdevice to start the app at a non-default address.