Hello,

NOTE: I also posted this on github:https://github.com/zephyrproject-rtos/zephyr/issues/27706 I don't know which channel is the correct one for these types of issues. 

I have a question about debugging. I am using a nRF52 DK with Zephyr (sdk 0.11.3). I debug with Segger Ozone, using the zephyr.elf file and the recommended configurations: Target Interface: SWD,Interface Speed: 4000 KHz.
I try to debug a peripheral application: samples/bluetooth/peripheral_hr (tested with other apps as well).

In order to debug I need to disable some optimizations. I tried to configure this in the prj.conf which is located in the application folder (samples/bluetooth/peripheral_hr/prj.conf).

My config file looks like this:

CONFIG_BT=y
CONFIG_BT_DEBUG_LOG=y
CONFIG_BT_SMP=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_GATT_DIS=y
CONFIG_BT_GATT_DIS_PNP=n
CONFIG_BT_GATT_BAS=y
CONFIG_BT_GATT_HRS=y
CONFIG_BT_DEVICE_NAME="Zephyr Heartrate Sensor"
CONFIG_BT_DEVICE_APPEARANCE=833

CONFIG_DEBUG=y
# CONFIG_NO_OPTIMIZATIONS=y

Without the debug configurations I can't traverse through the main.c correctly, but with the CONFIG_DEBUG flag enabled I can. But when I want to step in/over lines of code in:

zephyr/subsys/bluetooth/controller/ll_sw/nordic/lll/lll.c
or
zephyr/subsys/bluetooth/controller/ll_sw/nordic/hal/nrf5/radio/radio.c
and many more files in the controller

the debugger jumps to lines that doesn't exist or opens functions that are not present on that line. This is both for CONFIG_DEBUG and CONFIG_NO_OPTIMIZATIONS.

Somehow I think the bluetooth controller files for nordic are still optimized, and I can't find a method to disable the optimizations.

Also I found that enabling CONFIG_NO_OPTIMIZATIONS flag will not let me connect with the device anymore, is this intended?

Thank you,

Kind regards
John Hendriks