I'm using the IoT bootloader from NRF52 SDK 14.2. When the bootloader has nothing to do and starts the main application, the FDS calls all fail in the main application. When I clear the UICR (nrfjprog -f nrf52 --eraseuicr), my main application launches (without using the bootloader) and the FDS calls work, it is only when the main application is launched through the bootloader that they fail. What am I missing?