Installed nRF5_SDK_15.2.0_9412b96 and nRFGo Studio. nRFGo Studio fails to recognize the nRF52840 DK board. Screen like this:

It sees and correctly identifies the Segger chip. Neither "Recover" button nor "Enable reset pin" buttons have any effect.
Using IAR, I can load and debug the blinky example code, so I know that the link hardware and PCB are good.