App gets stuck when booted from bootloader (works fine without bootloader) - SDK15 - 0xCAFEBABE in registers

[Andy]

Hello,

I'm having a weird issue that I'm not sure how to debug. I have an app that I know works fine if programmed just with the softdevice. However, when I also program the bootloader, the app gets stuck when initializing the softdevice. I can't see any error codes, I just see all the debug output that happens before ble_stack_init() and then nothing. The bootloader works fine as far as I'm concerned.

How can I go about this problem? Thanks for your help!

I'm using Eclipse + ARM GCC 7.2.1 , SDK15.0, S132 v6.0.0, NRF52832.

EDIT: Just to be clear, the bootloader does jump to the app normally. My app actually starts running and then it stops

[Andy]

I'm no longer sure about where the program is getting stuck, but I looked at the registers by halting the processor after it gets stuck and they read this:

PC = 0007763E, CycleCnt = 3C7E5A37
R0 = 00000064, R1 = 0007763F, R2 = CAFEBABE, R3 = CAFEBABE
R4 = 00000204, R5 = 00000000, R6 = 20004158, R7 = 00000000
R8 = 00000003, R9 = 00000003, R10= 0004314A, R11= 2000FF94
R12= 00000000
SP(R13)= 2000FF58, MSP= 2000FF58, PSP= 00000000, R14(LR) = FFFFFFF9
XPSR = 21000019: APSR = nzCvq, EPSR = 01000000, IPSR = 019 (INTISR10)
CFBP = 00000000, CONTROL = 00, FAULTMASK = 00, BASEPRI = 00, PRIMASK = 00

How can I use that information to figure out what's going on?

[Nguyen Hoan Hoang]

How did you flash the DFU and your firmware ? It looks like DFU never jump to your firmware.  

To debug your firmware with DFU, first upload your firmware using DFU.  Then you can refresh firmware for debugging with Eclipse.  Important that the binary of your firmware must be the same in both cases.  

[Andy]

I'm sorry, I don't understand what you mean. I flashed the softdevice and the bootloader as usual with nrfjprog and a JLink. Then I did a DFU with NRF Connect for iOS. I can see that the bootloader is indeed jumping to the app because I'm getting a little bit of RTT output from the app, then it stops and I don't see anything anymore.

What makes you think the bootloader never jumps to the app?

[Nguyen Hoan Hoang]

The PC address looks like it's in the DFU code.

[Andy]

I have narrowed it down to this piece of code:

	uint32_t err_code;
	ble_dfu_buttonless_init_t dfus_init = {
		.evt_handler = ble_dfu_evt_handler
	};

	// Initialize the async SVCI interface to bootloader.
	err_code = ble_dfu_buttonless_async_svci_init();
	APP_ERROR_CHECK(err_code);

	if (err_code == NRF_SUCCESS) {
		err_code = ble_dfu_buttonless_init(&dfus_init);
		APP_ERROR_CHECK(err_code);
	} else {
		debug_error("Bootloader not found");
	}

Somewhere there it gets stuck.