Custom Bootloader

RE: Custom Bootloader

Hung Bui — Wed, 02 Aug 2017 13:35:27 GMT

Have you tried what I suggested ? Simply call nrf_bootloader_app_start() at the beginning of the bootloader ? If you still have error when doing so, you need to compare with the normal bootloader and check why it works there but not on yours.

RE: Custom Bootloader

mectronicsinc — Wed, 02 Aug 2017 11:53:11 GMT

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().

RE: Custom Bootloader

Hung Bui — Mon, 31 Jul 2017 14:42:25 GMT

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.

RE: Custom Bootloader

Roger Clark — Sun, 30 Jul 2017 22:32:32 GMT

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

RE: Custom Bootloader

mectronicsinc — Sun, 30 Jul 2017 10:00:22 GMT

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.

RE: Custom Bootloader

Roger Clark — Sat, 29 Jul 2017 22:16:33 GMT

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 ?.???