Hi,
I'm using nRF52832 and nRF52840 to work with MCU, then we should do the firmware update by the uart. I have compiled the bootloader_secure_serial project in the SDK 13.0 and then program it to the DK board, I run the command in the command line:
nrfutil dfu serial -pkg Blue5_test.zip -p COM5 -fc 1 -b 115200
It's OK. There is no flow control on my board, so I disable it in the serial_dfu_transport_init() function:
uart_config.hwfc = NRF_UART_HWFC_DISABLED;
Then run the command:
nrfutil dfu serial -pkg Blue5_test.zip -p COM5 -fc 0 -b 115200
But it couldn't update the firmware and get the error as follow: