I am using nRF52840 development software based on ble_app_uart_c, and I found that when I set NRF_LOG_DEFAULT_LEVEL as 1, if I download the software by Segger, the device worked well. If I updated the software by OTA, the devcie cannot start. If I set NRF_LOG_DEFAULT_LEVEL as 3, updating the software by OTA, the device worked well.