Unable to detect external device when programming custom PCB with nrf5340 via JTAG and nrf5340DK

[Marosh]

Hi, I have previously posted issue with flashing that was already solved.  Issues with flashing code on MDBT53V mounted on cusotm board 

Unfortunately for some reasons I had to send the nrf52840DK module to my colleague and I have currently only nrf5340DK version 2.0.2 at hand.

The setup is same as with as in the issue linked above with the only exception of using different DK to flash the external board (running on 1.8V). The issue I am facing is the fact I am not even able to detect the external connected PCB so I am technicaly not able to flash it.Tried to supply 1.8V on VTG or Vioref, short and unshort SB19, use different version of nrf connect in vscode but all without success. Also following this issues didnt helped:
Unable to flash custom nRF5340 board with nRF5340DK
I can't program external board with nRF5340 2.0.2    

Is there some difference between flashing with nrf52840DK and nrf5340DK I dont know about? Have I possibly damaged my dev board so it is no longer able to flash?

Regards,
Marosh

[PaKa]

There is a difference between DKs depending on which debugger is on the board. Have you made sure to connect ALL wires listed in the user guide and not taken shortcuts and not connected some of them? Missing wires is the number 2 failure mode, number one is difference in voltage level between external board and DK.