Can the bootloader directly boot into the app instead of into the softdevice?

RE: Can the bootloader directly boot into the app instead of into the softdevice?

Amanda Hsieh — Mon, 08 Feb 2021 09:15:57 GMT

Hi Rico,

No, you can't use the Softdevice SOC library when the softdevice is disabled or not enabled. In that case, just call the basic nrf driver functions which do the same thing, or write the registers directly. Many of those softdevice SoC functions only exist to guard shared resources when the SD is active and have one-line counterparts in the SDK.

-Amanda H.

RE: Can the bootloader directly boot into the app instead of into the softdevice?

rico — Mon, 08 Feb 2021 09:02:18 GMT

No problem Amanda.

I am using the nrfx_nvmc library. I am not using anything Softdevice related yet.

I have checked myself and found that the flash protection is set from the bootloader and not the soft device. So I either had to disable the protection or use the application settings page for storing data in flash. Which is fine.

So only the last question remains,

If I am NOT enabling the Softdevice, is it safe to NOT use the Softdevice SOC library? It isn't clear from the docs if this should only be used if the softdevice is enabled, or all the time when a softdevice is present in flash.

RE: Can the bootloader directly boot into the app instead of into the softdevice?

Amanda Hsieh — Mon, 08 Feb 2021 08:45:42 GMT

Hi Rico,

Sorry for the delay.

[quote user="rico"]I need to write to flash in my application an I am receiving an hard fault if I use the nrfx library to do so,[/quote]

If your application uses sd_function in the nrfx library, you have to enable the softdevice to access the Softdevice SoC library.

-Amanda H.

RE: Can the bootloader directly boot into the app instead of into the softdevice?

rico — Wed, 03 Feb 2021 14:09:53 GMT

Thanks for your detailed response. That's exactly what I would like to do. I have already tested the example but with version 7.0.2 Softdevice.

You say that the bootloader does directly boot the app without booting the Softdevice?

I need to write to flash in my application an I am receiving an hard fault if I use the nrfx library to do so, while booting the app through the bootloader. So it seems to me that the Softdevice has been involved and has placed memory protection on those areas. Or is this done via bootloader?

Also does this mean I do NOT have to use the Softdevice SOC management if I am not enabling the Softdevice?

RE: Can the bootloader directly boot into the app instead of into the softdevice?

Amanda Hsieh — Wed, 03 Feb 2021 08:30:51 GMT

Hi Rico,

I think you want to use BLE DFU to update your standalone application with no SDK integration to the device. If so, you can use BLE Secure DFU Bootloader, but the BLE DFU transport (see BLE) depends on the SoftDevice. For nRF52833, you can use <InstallFolder>\examples\dfu\secure_bootloader\pca10100_s140_ble. You will see the device advertise as DfuTrag. Also, see BLE Secure DFU Bootloader.

You can let the app start above the SD, and the bootloader will boot the app directly. If you use S140 v7.0.1 for the ble bootloader, the app should locate from the FLASH start 0x27000 and RAM Start 0x20001678. To generate the package to update, you can use this command:

nrfutil pkg generate --application app.hex --hw-version 52 --sd-req 0x00 --application-version-string "0.5.0" --key-file priv.pem package.zip

-Amanda H.