DFU Device Address Changes

RE: DFU Device Address Changes

Hung Bui — Mon, 07 Oct 2019 08:32:56 GMT

@Elias: Please create a new case with more information on what you want to know. This case is 4 years old.
The device address is random so the address +1 is also at the same level of randomness.

RE: DFU Device Address Changes

Elias Löwe — Mon, 07 Oct 2019 08:00:07 GMT

Can it happen that some device in DFU mode witll have the same address with any regular Nordic device?

RE: DFU Device Address Changes

Jordan Archer — Wed, 07 Oct 2015 20:48:46 GMT

So that code wasn't in the 7.0 SDK. But it works. Thanks!

RE: DFU Device Address Changes

Hung Bui — Tue, 06 Oct 2015 08:53:20 GMT

@ Jordan: If you use SDK v9.0 you can find this code:

ble_gap_addr_t addr;

        err_code = sd_ble_gap_address_get(&addr);
        APP_ERROR_CHECK(err_code);

        // Increase the BLE address by one when advertising openly.
        addr.addr[0] += 1;

        err_code = sd_ble_gap_address_set(BLE_GAP_ADDR_CYCLE_MODE_NONE, &addr);
        APP_ERROR_CHECK(err_code);

From line 1065 to 1074 in dfu_transport_ble.c

RE: DFU Device Address Changes

Jordan Archer — Mon, 05 Oct 2015 19:56:05 GMT

I don't see where in dfu_transport_update_start you change the address. How does this happen?

RE: DFU Device Address Changes

Hung Bui — Wed, 06 May 2015 10:51:54 GMT

@Lucas: By design our Bootloader will use a different address from the default address in FICR (FICR address + 1) if there is no bond information shared. Please have a look at dfu_transport_update_start() in dfu_transport_ble.c

The reason we do that is to solve the issue that the central device (phones, tablets) may try to use the bond information it has before with the normal application to encrypt the link. If we don't have shared bondinformation, we won't be able to follow the encrypted link when in bootloader mode. So we change the address and will be recognize as a new device from the phone and can avoid the above issue.

EDIT: It's not only when there is bond information share but also when a central address is shared, the address will not change. It only changes when the bootloader started up from booting (no bond information or address shared)