Can I erase UICR in ble app or must erase all chip and write uicr again?
I received an answer on Nordic's support portal. To erase the UICR, you must erase all flash. Nordic reasons that if the UICR can be erased while running then the readback protection configured in the UICR can be defeated.
update: nrf52 has a different memory protection implementation and allows the UICR section to be erased at runtime.
