Not able to flash nrf52840 DK unless the reset pin tied to NRF_VDD

[ZebbleMan]

I'm going through the Academy courses and somewhere around Lesson 3, I could no longer flash firmware to the nrf52840 DK.

I browsed the forum and found some notes around erasing the UICR (nrfjprog --eraseuicr   / nrfjprog --recover) that run successfully with P0.18 tied to VDD but I still can't flash the board without P0.18 tied to VDD.

I was trying some other 3rd-party firmware examples in between all of this, which I believe caused the issue but I can't seem to get back to the factory config for the board and continue with the Academy course!

Any help is appreciated.

[ZebbleMan]

Did some additional digging...

I had the power profiler 2 connected to the nrf52840-dk in ampere/current mode.  I've removed that and jumpered P22 and now everything is working as expected!

I know I had installed a few firmwares in this config and everything worked.  Not sure why it decided to stop working.

I see one note that references this in the PP2 docs:

"To reprogram the nRF52840 SoC while the DK is prepared for current measurements, remove measurement devices from P22, and then connect the USB cable."

So I guess this is normal and what I initially saw was a fluke?

Anyway, back to the academy courses.