Custom Bootloader

[mectronicsinc]

Hi all,

I'm trying to write a custom bootloader that must works in this way:

1. The new image to flash is received by a uBlox GPRS modem that communicates with the nRF52832 using the SPI;
2. Through SPI, I'm able to read the new binary file, validate him, and after, write the flash starting @ 0x0001F000 (I'm using S132 V3.0);
3. I update the Bootloader Settings;
4. After, when I call the nrf_bootloader_app_start(MAIN_APPLICATION_START_ADDR), that arrives until the last subfunction (nrf_bootloader_app_start_impl), the process remains locked and the new app don't starts;

The nRF52 is mounted in a custom board.

Any idea because this occurs?

Thank you!

[Roger Clark]

Is the all the code you described in your post inside the bootloader?

I presume you took the UART bootloader as your starting point ???

So the process, is that first the application receives notification there's is a new application, and it resets the system onto your custom bootloader, which loads via SPI ?.???

[mectronicsinc]

Hi Roger,

Yes, all the steps I've described are done in the Bootloader. My starting point has been the secure DFU bootloader, I've "cut" all the unnecessary code, keeping, obviusly modified, the enter check.

Yes, the main app receives a notification by the modem when there's a new application and then perform a system reset. Of course, this check is done also every time the circuit is powered.

[Roger Clark]

Impossible to tell whats going wrong unless you post all your code, and I doubt anyone would have time do debug it for you.

However one interesting thing you said is "I've cut all the unnecessary code"

I wonder if you cut something necessary

[Hung Bui]

Do you see the PC jump to the start_addr after nrf_bootloader_app_start_impl() ?

I agree with Roger, maybe you missed something important. You can test the nrf_bootloader_app_start() function by flashing the application manually using SWD, then call nrf_bootloader_app_start() in the bootloader to jump to the application.

[mectronicsinc]

Hi. I saw the jump after nrf_bootloader_app_start() (NOTE: I DO NOT modified this function: the code I removed/changed is just the boot enter check criterion..). The execution is locked @ 0x1E088 (--> LDR R3, [R3, #0xC]), that is a SD code address. This occours when nrf_bootloader_app_start() calls sd_softdevice_vector_table_base_set().