Programming custom board vs Arduino bluefeather nrf52852

Hello, 

I am trying PCA10040 examples on bluefeather arduino board , all of them works perfect and i am programming those examples by using jlink and ses. But when i try the same examples with the same setup and tools on my custom board, the only examples with no SD ones are working. If there is any softdevice in the example project, p0.17 is blinking and thats all. I assume it can not boot. When i swap chips between bluefeather and my custom boards everything works as expected on my custom board with the nrf52 that i transferred from arduino board. 

When i check the PCA10040 examples which has sd , they contain sd  hex too. How can i solve this problem. As i know bootlaoder is located in Sd hex .

Update:

The problem occurs if i not "erase all" before i download anything tonrf52.

Next question is , why doesnt it works without "erase all" , i mean it alresdy burns sd and app together , what prevent it to boot?

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