Sending Response: [0x4, 0xB] in serial DFU ?

[mayuri]

 Hi,

I m using nrf52840 and m doing DFU over serial.

one side is master controller and other end is NRF DFU serial(secure bootloader uart debug code).

After sending init packet. i m getting correct CRC value from NRF by sending value 03.

And then i m sending 04 command.I m getting 0b response in master mcu. 

Here following error on nrf side

<warning> nrf_dfu_ver_validation: SD req not met.
<debug> nrf_dfu_req_handler: Request handling complete. Result: 0xB
<warning> nrf_dfu_serial: DFU request completed with result: 0xB
<debug> nrf_dfu_serial: Sending Response: [0x4, 0xB]
<debug> app: Shutting down transports (found: 1)

i have no idea why its coming response like 0b.

i would appreciate any help

thnaks in advance.

[mayuri]

i m sending only command to enter booloader (second time).

1) when i connect rtt viewer , it hold on (ie bootloader mode.)

At the time i m sending dfu transfer, i not getting even ping response.

2) when i remove rtt viewer,it is entering into bootloader and then resetting back to previous application mode.

I m not including BL setting in Step 1.

it may cause any error

[mayuri]

it s working now.

the problem is application watch dog timer.now i increased watchdog greater than bootloader tinne inactivity. the reset wont happen it again.

Thanks for your support