Need help on enabling MCUBoot on a custom board based on the NRF5340 (BL5340PA) using internal flash for ncs version 2.6.2

Hello, I' needing some help on setting up the MCUBoot for the BL5340PA using the ncs 2.6.2. Currently I have the below add on for the prj.conf for the application core:

CONFIG_BOOTLOADER_MCUBOOT=y
CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y

The built successfully went through but the problem is that I can't see the BLE device anymore and I don't really know where to start to debug the problem as the image was built with mcuboot enable. 
Would be greatly appreciated if anyone can provide a step by step walkthrough the process of setting up the MCUBoot for the nrf5340 (BL5340PA) on the ncs 2.6.2 ! 
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