Customizing a bootloader

[p143]

If all you need is changing  PHY, Tx power and Device Name in a standard nRF52840, do you need building a new bootloader from the scratch or the is a way to edit the standard firmware,  build a new edited file and finally re-program this file in a standard nRF52840? Thanks

[Vidar Berg]

You are free to modify the bootloader as you want. That is, you should not disable the signature check as long as you use our service uuid reserved for secure DFU.  The bootloader projects can be found in the following directory: \nRF5_SDK_15.2.0_9412b96\examples\dfu\secure_bootloader. Also, if you are new to our bootloader implementation I recommend you to have a look at this blog post: https://devzone.nordicsemi.com/b/blog/posts/getting-started-with-nordics-secure-dfu-bootloader 

[p143]

Hi Vidar. I follow the step by step guide which is being mentioned in your blog post link, but I get this error, in Spanish: 

------------------------------------------

PS C:\nordic\pip> python get-pip.py install
python : El término 'python' no se reconoce como nombre de un cmdlet, función, archivo de script o programa
ejecutable. Compruebe si escribió correctamente el nombre o, si incluyó una ruta de acceso, compruebe que dicha ruta
es correcta e inténtelo de nuevo.
En línea: 1 Carácter: 1
+ python get-pip.py install
+ ~~~~~~
+ CategoryInfo : ObjectNotFound: (python:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException

PS C:\nordic\pip>

--------------------------------------------

Which briefly translated means: The term 'python' is not being recognized as a cmdlet name, script file or executable program. make shure ....

Of course, the directory (PIP) containing the get-pip.py file, has been set in the Windows Path.

Any suggestion to solve the problem?

Thanks

[Vidar Berg]

Hi, 

I belive pip is included in the latest python releases. I'd suggest that you download and install the latest 2.x.x release: https://www.python.org/downloads/. Also make sure that  \Python27\ and \Python27\Scripts gets added to your PATH variable so you don't get the  "'python' is not being recognized" error. 

[p143]

Hi Vidar.

Following your advice, the problem has been solved. Thanks.

And by the way. Let me take this opportunity to ask you a terminology question. When  Nordic guides refer to "the bootloader", is the term completely equivalent to "the firmware"? And also. What the bootloader contains?: booting code+one application+one softdevice+MBF+something else maybe? Is this Softdevice the S140 SDS or there are different types of Softdevices? Thanks for the clarification.

[Vidar Berg]

Hi,

The bootloader is a separately linked "application" with is own vector table, same applies to MBR, Softdevice and the main Application (note: the softdevice binary is merged with MBR image). Maybe it gets more clear if you have look at  the bootloader memory layout here: http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.2.0/lib_bootloader.html?cp=4_0_0_3_5_0_7#lib_bootloader_memory  All of the DFU functionality is implemented in the bootloader code and bootloader is also in charge of validating and booting the main app. 

There are different softdevice variants, but only s140 is compatible with the nRF52840 (combability matrix).