Buttonless DFU service does not start when NRF_LOG_ENABLED is set 0

[AntonHellbe]

Hi all,

I have a very strange problem with the Buttonless DFU service. For my project we have two different builds, one debug and one "release" build. The debug build sets the following SDK config defines to 1, and the release build sets them to 0.

• NRF_SDH_BLE_LOG_ENABLED
• NRF_SDH_SOC_LOG_ENABLED
• NRF_SDH_LOG_ENABLED
• NRF_LOG_BACKEND_RTT_ENABLED
• NRF_LOG_ENABLED

When I compile the project and flash the debug build (application + softdevice + bootloader) the application starts up and I can access the DFU service. However when I compile and flash the "release" build the application does not start. If I remove the DFU service the application starts up with both builds, so there's something happening when I disable the logs with the DFU service. Its very hard to debug since everything works the logs are enabled.

I've had some issues before with observers being optimized way since the source code from the libs is not being directly referenced from my code. Could it be something similar going on here? https://devzone.nordicsemi.com/support/224969 (Private ticket)

All help is appreciated, this is a very annoying problem!

[Vidar Berg]

Hi,

Maybe I'm way off but I wonder if it could be caused by an invalid CRC value in your bl settings page which would cause the bootloader to enter DFU mode. Is this page being re-generated each time you compile the app? As you may know, the settings page includes a CRC checksum value of the app image which must match the CRC of the actual app image stored in flash. The bootloader will not "jump" to the application if there's a mismatch. Does your device appear to be stuck in DFU mode? 

[AntonHellbe]

Hi Vidar,

Yes everytime we flash we re-generate the settings page.

I know that the bootloader starts the application because we have different "modes" in the application, 2 of them does not use the DFU service. When I put the nRF52832 in one of the two other modes that does not use the DFU service I can see the advertisement and I can connect.

/ Anton

[Vidar Berg]

Thanks for the clarification. It sounds like we would need to debug the application to figure out why the program hangs when you select DFU mode. Have you tried to disable logging in the 'debug' target to see if it has the same effect? I guess it could be related to other differences such as compiler optimization as well.  

[AntonHellbe]

Hi Vidar,

Thanks for the tips. I disabled logging in the "debug" build and it kept working. So there is something in our release build that causes the application not function properly.  From what I can see all we do in our release build is that we set an additional preprocessor flag that removes the logs, see below:

ifeq ($(ENABLE_LOGGING),)
$(info ENABLE_LOGGING not defined, using default ENABLE_LOGGING=1.)
else
$(info ENABLE_LOGGING=$(ENABLE_LOGGING))
CFLAGS += -DENABLE_LOGGING=$(ENABLE_LOGGING)
endif

Anyways, I think we will have to investigate further our side. Thank you so far.

Edit: the preprocessor flag which you can see above being set is then being used in the sdk_config.h file.

/ Anton