STM32 NRST being held low
I measured the resistance from NRST to GND and it was ~2k. I de-soldered the MCU and re-measured the resistance from NRST to GND, which was now larger than 20M.



The internal circuitry is just a pull-up and schmitt trigger, so I concluded that there was some internal short in the MCU, which is backed up by bizarre behavior by the MCU beyond this NRST problem. I cannot double check this with another MCU as the pads are messed up from all the rework now.