Adding the chip holder was slightly tricky. I didn't have Via on my board and I soldiered the chip from the back.
Later I realized that I should have soldiered it from the top. To fix this I resoldered the chip holder again from the side.
Also there was no connection from SCK to PB2. It was in my schematic but I guess I missed the connection while routing.
So I used a thin wire to fix it.