Cannot jump to application from bootloader, bootloader crashes/freezes

[Andy]

Hello,

I added an extra opcode to the DFU Control Point characteristic so that I can jump to the main application by writing to it. The problem is that whenever I do that, the bootloader freezes (it doesn't reset). I'm on SDK13.1, using S132 4.0.2 on an NRF52832

This is what my code looks like:

case BLE_DFU_OP_CODE_BOOT_TO_MAIN:
        	NRF_LOG_DEBUG("- Received boot to main command\r\n");
        	if (nrf_dfu_app_is_valid())
			{
        		res_code = NRF_DFU_RES_CODE_SUCCESS;
        		response_send(p_dfu, BLE_DFU_OP_CODE_BOOT_TO_MAIN, res_code);
				NRF_LOG_DEBUG("Jumping to: 0x%08x\r\n", MAIN_APPLICATION_START_ADDR);
				nrf_bootloader_app_start(MAIN_APPLICATION_START_ADDR);
			}
			res_code = NRF_DFU_RES_CODE_OPERATION_FAILED;
			return response_send(p_dfu, BLE_DFU_OP_CODE_BOOT_TO_MAIN, res_code);

The application freezes for some reason inside nrf_bootloader_app_start(). Other calls to that function work as expected, but not that one.

I looked at this thread, but I can't pinpoint what I need to do to fix it: application can not start normally in merged hex (SD+APP+BL)

I'm guessing that in that case, the program is in a state where the SoftDevice somehow crashes when calling nrf_dfu_mbr_init_sd() (which I don't really understand what is for).

Any help will be appreciated!

[Hung Bui]

Hi Andy,

Could you print out some log from inside nrf_bootloader_app_start() to check where there program stucks? nrf_dfu_mbr_init_sd() is the call to initialize the softdevice from the bootloader. I don't think you should have any problem calling it.

[Andy]

Unfortunately, I can't. Everything stops working after the program enters nrf_bootloader_app_start(). I have a blinking LED and it stops blinking. The logs stop a bit before entering that function, but I guess that's because something went very wrong and it didn't have the chance to print the missing logs.

[Hung Bui]

Can you just use a LED to check which line of code it's getting to ? (move one line of code at a time) You can also run the bootloader in debug mode and add some break points ?