OTA DFU bootloader

[Cy]

I am having some success with custom hardware running an OTA DFU bootloader from the SDK17 by Hung Bui March 2017 within a nRF52832. I utilize the bootloader to program the ble_app_uart into the hardware and things work as expected. I do have trouble when I load an app with no soft device. It appears to load but will not run the app that runs the display, just hangs. The tutorial describes how to perform a zip of the application, but the description has a option with the softdevice, but the application has no SD.

Can the bootloader program an application without an SD and run the application without problems?

[Turbo J]

You need to modify the linker script/settings for the application.

Reason: The SD has to stay in place - otherwise the OTA DFU bootloader won't work. Thus the application has to occupy the flash area after the SD. You also need to reserve a small amount of RAM (8 bytes IIRC) for the Softdevice - even when it is disabled - in order to use interrupt forwarding.

An unmodified app would occupy the space for the SD in flash - this should be rejected in the bootloader logic. And no, cannot run a statically linked app from a flash address other than it was linked to.

[Cy]

The tutorial utilizes the 

nrfutil pkg generate --hw-version 52 --application-version 1 --application _build/nrf52832_xxaa.hex --sd-req 0xCB --key-file private.key app_dfu_package.zip

to zip the application. Can this same utility be used to zip the app in the correct way? The option of the --sd with the version 7.0.1 is being used but I dont think it will run properly without the option, but will run with the option being 0x00.

[Cy]

Well, utilizing the nrfutil and the 0x00 on the sd option will zip and data transfers but will not run the application. 

[Amanda Hsieh]

Hi, 

Cy said:

nrfutil pkg generate --hw-version 52 --application-version 1 --application _build/nrf52832_xxaa.hex --sd-req 0xCB --key-file private.key app_dfu_package.zip

If you already programmed the  s132_nrf52_7.0.1_softdevice.hex and only want to only update the app, your commend is correct. You can test with the hrs_application_s132.hex nRF5_SDK_17.0.0\examples\dfu\secure_dfu_test_images\ble\nrf52832

-Amanda H. 

[Cy]

Hmm, I have no use for hrs_application_s132.hex, and that is a soft device application. I have a situation where the application useful to me does not require a soft device. Well, I guess it is prudent to dig into the bootloader program and the linker script to figure out where, what, and how. 

[Amanda Hsieh]

Hi Cy, 

Sorry for misunderstanding your situation. 

--sd-req should be the same version as the softdevice on the chip because the bootloader will check the version number. But it doesn't care the app will use it late or not. 

Cy said:

I have a situation where the application useful to me does not require a soft device. Well, I guess it is prudent to dig into the bootloader program and the linker script to figure out where, what, and how. 

 Yeah, I agree with Jörg Fischer's suggestion. You can have an application that doesn't use the SoftDevice. You only need to change the FLASH and RAM start address and size. You can test and modify nRF5_SDK_17.0\examples\peripheral\blinky\pca10040\mbr with the FLASH and RAM start address and size in nRF5_SDK_17.0\examples\peripheral\blinky\pca10040\s132.

Right-click on the project -> Common -> Linker -> Section Placement Macros

-Amanda H.