In my previous ticket regarding DevAcademy tutorial for nRF 52840 I already mentioned. that starting from lesson 2 iPhone cannot communicate with the board and the VS Code terminal was not working.
I guess I found the source of misbehavier, but don't know how to fix it. What I found is that Flashing process at Lesson1 is different from Flashing at Lessons 2, 3, and 4.
Attached are results of Flashing in Lesson 1 and Lesson 4.
Lesson 1 Exersise 1


Lesson 4 Exersise 1

Thanks,
Steven.