Default boot-loader for dongle

[Hiihtaja]

Hello !

1. I have found in internet bootloader for dongle graviton_bootloader_mbr_v1.0.1-\[nRF5_SDK_15.0.1-1.alpha_f76d012\].hex and able to flash and use it.

   But where I can found latest version of precompiled bootloaer what is based on latest SDK ?

  Or it should be compiled by myself from some known sources  ? Please point me to right page/code.

2. By using the bootloader and nrfutil, I'm able to create dfu.zip and update application only.

BUT

how  issue SW reset by using nrfutil without actual update ?

Sometimes I put dongle like HW to DFU by Reset mode and need to reboot it to normal boot without power on/off operation ?

How to erase application without actual update of it ? Just bootloader should remain.

Regards,

Eugene

[Maria Gilje]

Hello Eugene,

I will take a look at this and get back to you after the weekend.

Thank you for your patience.

Kind Regards,
Maria

[Simonr]

Hi Eugene

Sorry about the late reply, but we don't have an updated .hex file for the later SDK versions, as not too much has changed in the USB bootloader area since nRF5 SDK v15.

As the Dongle Programming tutorial explains, you can also use the Open Bootloader example from the later SDKs, although this doesn't include the public key needed to update the bootloader itself over USB DFU. This can be added with slight modifications though.

Best regards,

Simon

[Hiihtaja]

Hi Simon !

So in common case, you suggest to use Secure Bootloader https://infocenter.nordicsemi.com/index.jsp?topic=%2Fsdk_nrf5_v17.1.0%2Fble_sdk_app_secure_bootloader.html

source as a base and maintain own bootloader especially in cases when security/signature check is required ( typical production case ) ?

Looks like only legacy nrfutil v6.x is available in the source code ( I need flasher for  Rpi arm platform ) and from the roadmap is not so clear what bootloaders support what protocols.

Regards,

Eugene

[Simonr]

Hi Eugene

I would recommend the Open bootloader that has more relaxed security compared to the secure one, and makes it easier to add the public key that's required to update the bootloader itself over USB. But it should be perfectly fine using the older .hex file as well unless you want to implement some custom features to your bootloader.

Best regards,

Simon

[Hiihtaja]

Hi Simon !

Do you have idea if nrfutil can reboot nRF to normal mode ?

It happens after update automatically but sometimes it need back without update e.g if someone put it to DFU and power ON/OFF is npt possible.

Regards,

Eugene