hello world+ mcuboot is not working

[99003662]

hi ,
I am using stm32 board , while i was testing an mcuboot example (zephyrproject/bootloader/mcuboot/samples/zephyr/helloworld) ,
1.this example is building fine, after flashing the code board is not printing the printk statements from main(helloworld/main.c).
2. I have a doubt whether it is including the mcuboot while building or not , so I have added couple of printk inside the bootloader main.c file(bootloader/mcuboot/boot/zephyr/main.c) , even I didn't get any prints.

Note- using west tool to build , board - stm32f767

Kindly help me to figure this out.
Thanks