After DFU update Device does not reset

[ssc]

Hello,

 I have issue that after firmware update in DFU mode through BLE device does not reset. If i test updating firmware for 10 to 20 times then 4 to 5 times it does not get reset in rest cases get reset. Could not find any such reason for such observation.

I have referred below links but no luck:

1)https://devzone.nordicsemi.com/f/nordic-q-a/48103/nrf52-does-not-reset-after-dfu

2)https://devzone.nordicsemi.com/f/nordic-q-a/34224/device-does-not-reset-after-dfu

I am using SDK 15.2.0 version. IDE used is Segger embedded studio which shows Toolchain version 7-2018-q2-update source distribution. 

Link 2  has suggestion to not build the code with -flto option, I could not find where to edit this. Please help for the same.

Also is it possible to downgrade the segger embedded studio to GCC 6 ? or what alternative i should follow? 

[Amanda Hsieh]

Hi, 

I am using SDK 15.2.0 version. IDE used is Segger embedded studio which shows Toolchain version 7-2018-q2-update source distribution. 

Could you use GCC ARM Embedded 6.3 2017-q2-update as our suggestion in nRF5 SDK v15.2.0?

The Link Time Optimization(LTO) issue occurred when using a GCC version that was not production tested with the nRF5 SDK, e.g. using GCC ARM Embedded 7 instead of GCC ARM Embedded 6.3. We also do not see any issues with LTO when using the correct GCC version.

-Amanda H. 

[ssc]

I have solved this issue by changing the bootloader mode entering method. Previously I was using DFU service in my main application. Now I am using the GPREGRET register method to enter bootloader mode and resetting the device. This is making my OTA process faster as well as the issue of disconnection after entering bootloader mode is also covered.