NRF52 OTA DFU bootloader too slow

[jonas.woerner]

Hi,

our application is nearly finnished now, but I noticed, that after adding the secure_ble bootloader, the program enters the bootloader at poweron, then enters my application, but it takes about a full 1-2 seconds until it enters main. my application has to start really fast, so it would be great if the bootloader wouldnt take more then a few ms, if any.

Is it possible to boot directly to the application without the bootloader in between, and only start it when needed with the GPREGRET + reset? maybe with a setting in the bootloader settings file?

thanks,

Jonas

[Vidar Berg]

Hi Jonas,

It's not possible to skip bootloader execution on startup as it is responsible for validating the main app, but it should only take a few milliseconds to do so. Have you made any changes to the original bootloader code that could potentially delay startup? 

Best regards,

Vidar 

[jonas.woerner]

hrm. all I did was changing the RSA key. without bootloader my app starts almost immidately, with bootloader it takes 2-3 seconds. I am using the SDK14 with S140 alpha softdevice ( I cannot use any other for the moment)

any more Ideas?

[Vidar Berg]

Have you tried to debug the bootloader project to find out what's delaying the startup? Since the delay is several seconds, it should be possible to halt the CPU during startup to see where the program is "stuck" (repeat a few times to verify that stops in the same address range).

Also, please note that you need to migrate your code to SDK 15/s140 6 before you go in production. The SD/SDK combo you're using is not production-ready. The MBR included in the alpha release will for instance not support DFU of the bootloader itself. This means that you can't DFU to Softdevice version 6 or 7 either.