jump to bootloader with nrfutil

[ms360]

Hi!

I've used nrfutil to dfu ble before on a target that just loads and runs a bootloader (for cycle testing).

I'm trying to use it again with a target in the application, before the bootloader jump. 

I keep getting timeouts in this case. 

The NRF DFU and NRF connect apps will jump from application to bootloader. 
Is nrfutil also capable of this? 

[Priyanka]

Hi,

nrfutil dfu ble cannot trigger the application to jump to the bootloader. i.e., the device must already be in DFU mode before starting the update with nrfutil.

-Priyanka

[ms360]

Thanks Priyanka. 

related question -  Is there something that can be scripted to send the bootloader jump command via the DFU characteristic?

[Priyanka]

Hi,

Are you working with our old nRF5 SDK, or are you using the nRF Connect SDK? If so, which version?

You mentioned a bootloader, by that, do you mean MCUboot? If not, please clarify. Also, if you are using the nRF5 SDK  and nrfutil nrf5sdk-tools dfu ble, please note that this assumes the device is already in bootloader mode

-Priyanka

[ms360]

Thanks Priyanka. 

we're using nrf5 SDK

Do you know what packet/characteristic NRF DFU sends to jump from application to bootloader? 

[Priyanka]

Hi,

The central writes the single-byte opcode 0x01 (Enter DFU mode) to the appropriate Buttonless DFU characteristic UUID 8EC90003-F315-4F60-9FB8-838830DAEA50 if not bonded, or 8EC90004-F315-4F60-9FB8-838830DAEA50 if bonded, after enabling indications. Upon receiving this write, the device stores a DFU flag in GPREGRET, performs a system reset, and the bootloader begins advertising the Secure DFU service so the firmware update can proceed.

See the sections Buttonless Service, Operations and Format, and Enter DFU Mode in here.

-Priyanka