SDK v15 DFU Bootloader hangs on execute instruction

RE: SDK v15 DFU Bootloader hangs on execute instruction

dingari — Mon, 28 May 2018 12:12:36 GMT

Hi Bjorn, you can disregard my previous answer.

There were some files that the secure bootloader example was compiling and I wasn't. Everything seems to be in order now.

RE: SDK v15 DFU Bootloader hangs on execute instruction

dingari — Mon, 28 May 2018 09:49:59 GMT

Hi Bjorn, sorry to wake this old thread.

However, I'm facing a related issue now. My current devices, which have been programmed with the secure bootloader from SDK v12.2.0, can't be updated with the new bootloader via OTA DFU, since the new bootloader size is different from the old (0x8000 vs 0x6000).

After looking at the Makefile for the BLE Secure Bootloader, I can see that -flto is present in the CFLAGS, and the size is set to 0x6000 in the linker file. So I'm quite puzzled why the bootloader is misbehaving in my case.

I'm thinking about trying a newer version of GCC and see if the bootloader works with link time optimization. Otherwise I need to open all my current devices and re-flash the firmware via SWD, which is really not an option.

RE: SDK v15 DFU Bootloader hangs on execute instruction

Bjørn Kvaale — Fri, 13 Apr 2018 10:44:07 GMT

Not exactly sure why this is the case. This blog post says the following:

"NOTE: The safe thing to do is to assume that the flags that aren't included in the default Makefiles are just as interesting as the ones that are. For example, the Link Time Optimization (-flto) flag was dropped starting with SDK v9 when GCC was upgraded to v4.9. The rationale for this change isn't obvious but as far as I know it was intentional (and -flto hasn't been reintroduced)."

This case might also be helpful. It seems that none of our examples are compiled with Link Time Optimization & therefore not tested either. Those are my best two guesses as to why this is the case. Hope that helps a bit!

RE: SDK v15 DFU Bootloader hangs on execute instruction

dingari — Thu, 12 Apr 2018 14:01:29 GMT

Yes, removing the -flto allows the bootloader to behave normally. I'm curious as to why this is happening. Of course I could remove the flag, but then I have to increase the size of the bootloader code (around 8kB seems to do the trick). It's not the end of the world, but a smaller bootloader is preferrable.

RE: SDK v15 DFU Bootloader hangs on execute instruction

Bjørn Kvaale — Thu, 12 Apr 2018 13:22:20 GMT

Are you saying that everything works fine if you remove the -flto flag? This devzone case gives you a bit more information. If everything does work without this flag, could you not just remove the flag. It seems there is not too much performance difference from what I understand.

RE: SDK v15 DFU Bootloader hangs on execute instruction

dingari — Thu, 12 Apr 2018 09:52:03 GMT

Hmm, looking at nrf_bootloader_dfu_timers.c I'm suspecting the infinite loop is occurring due to a failed `ASSERT` on a return code from the timer module in this function:

static void timer_start(app_timer_t * p_timer, uint32_t timeout_ms, nrf_bootloader_dfu_timeout_callback_t callback)
{
    ret_code_t err_code;

    timer_init();

    err_code = app_timer_stop(p_timer);
    ASSERT(err_code == NRF_SUCCESS);

    if (timeout_ms != 0)
    {
        //lint -save -e611 "Suspicious cast"
        err_code = app_timer_start(p_timer, APP_TIMER_TICKS(timeout_ms), (void *)callback);
        //lint -restore
        ASSERT(err_code == NRF_SUCCESS);
    }
}

I had to disable link time optimization to have the necessary debug symbols available in gdb for debugging. However, without the -flto flag the bootloader doesn't crash... So I'm at a loss on how I can debug this.

RE: SDK v15 DFU Bootloader hangs on execute instruction

Bjørn Kvaale — Thu, 12 Apr 2018 09:07:54 GMT

This case was not assigned to my group. Another application engineer will look at your question as soon as they have time.

RE: SDK v15 DFU Bootloader hangs on execute instruction

Takeshi Goda — Thu, 12 Apr 2018 06:19:01 GMT

https://devzone.nordicsemi.com/f/nordic-q-a/33310/invert-pwm-behaviour

Can you tell me how to solve this problem?

RE: SDK v15 DFU Bootloader hangs on execute instruction

Bjørn Kvaale — Thu, 12 Apr 2018 06:14:52 GMT

Looking at the secure dfu bootloader example in sdk 15, the function nrf_bootloader_dfu_inactivity_timer_restart() gets called twice: once in the dfu_observer() function inside nrf_bootloader.c to handle the NRF_DFU_EVT_OBJECT_RECEIVED event & once in nrf_bootloader_init() also in nrf_bootloader.c.

Having you tried adding some NRF_LOG_ERROR() calls to debug the bootloader with an RTT client? I would try that to figure out where the error is occuring.

RE: SDK v15 DFU Bootloader hangs on execute instruction

dingari — Wed, 11 Apr 2018 09:09:54 GMT

I think these are the relevant lines in the .map file for the bootloader:

0x000000000007c1a0 nrf_bootloader_dfu_inactivity_timer_restart.constprop.38
0x000000000007c20c image_copy.part.0.constprop.35

I'm not sure where the infinite loop is occurring, but it's triggered somewhere after I issue an Execute command after sending the first object of the firmware.

RE: SDK v15 DFU Bootloader hangs on execute instruction

Bjørn Kvaale — Wed, 11 Apr 2018 08:24:19 GMT

Could you take a look at the .map file & see where in the code 0x0007c1ea corresponds to? Where is the infinite loop occurring? You can find the .map file in your build folder.