DFU secure bootloader loads softdevice in application area

RE: DFU secure bootloader loads softdevice in application area

Wojtek — Wed, 18 Oct 2017 09:37:14 GMT

Thanks for the answer Bjørn :)

RE: DFU secure bootloader loads softdevice in application area

bjorn-spockeli — Wed, 18 Oct 2017 08:48:12 GMT

Hi Wojtek, you can read about the update procedure here.

In your specific case the available flash for storing the new SoftDevice in Bank 1 alongside the application will be Bootloader Start Address - Address of first flash page after Application End Address`--> 0x37C00 - 0x29000 = 0xEC00 = 59kB. The S130 v2.0.x needs 104kB so the bootloader is forced to use the combined space of Bank0 and Bank1, i.e. Bootloader Start Address - Application Start Address( 0x37C00 - 0x1B000 = 0x1CC00 = 115 kB).

RE: DFU secure bootloader loads softdevice in application area

Wojtek — Mon, 16 Oct 2017 15:12:10 GMT

I have nRF51 QFAC (32 kB flash).

Memory organization:

0 - 0x1B000: s130,
0x1B000 - 0x37C00: my application (but program ends at 0x28400 according to output from nrfjprog),
0x37C00 - 0x3CC00: DFU secure bootloader,
0x3CC00 - 0x3D000: bootloader settings,
0x3D000 - 0x40000: untouchable piece of garbage.

So, as I understand, when I'm updating SD, it is written into application area if I have not enough memory? Where should I have this free space? How much is it "enough"? Is there any place, where may I read about this DFU behaviour?

RE: DFU secure bootloader loads softdevice in application area

bjorn-spockeli — Mon, 16 Oct 2017 14:04:06 GMT

Which nRF51 variant are you using? If there is not enough flash space to store both the application and the new SoftDevice image in addition to the bootloader and the old SoftDevice, then the application will be erased and the new softdevice will be placed in the application region, i.e. bank 0.