NRF52840 not detected on computer after entering bootloader mode.

[sne_333]

While testing DFU for OTA ,after entering bootloader mode on my nRF52840 DK, the device doesnt show up either in the device manager or using nRFconnect and Jflash lite .
when I turn the DK on and off normally (without pressing the reset button), the LD5 doesnt blink or turn on otherwise.

If I turn the board on while holding reset, BOOTLOADER shows up as a USB device, and the LD5 blinks. I see a folder for USB detection in My computer only for a second and then it vanishes. Can anyone help me how to recover my board?

Thanks in advance.

[Jørgen Holmefjord]

Hi,

If you have entered bootloader mode for the interface MCU, its firmware have been erased. You need to reflash the firmware in order to recover the board.

The default Segger J-Link OB firmware can be found here: J-Link-OB-SAM3U128-V2-NordicSemi-170724.bin 

The firmware is flashed to the board by entering bootloader mode (hold IF BOOT/RESET while powering board), then drop the binary to BOOTLODER drive. After a few seconds, you can unplug and replug the board and it should work like normal.

Best regards,
Jørgen

[sne_333]

Yes this worked for me. Thank you so much :)