nRF52840DK Bricked

[EthanH]

Hello,
Recently I tested and flashed the Zephyr program to the nrf52840DK, it works fine. While I flashed as usual last time, I saw the LED5 flashing and then the PC didn't recognize the USB connection. After reconnection, the LED5 is always off now and no any response in the PC.

Aa checked the online info, I followed the suggestions here:

devzone.nordicsemi.com/.../my-nrf52-nrf51-dk-kit-doesn-t-work
1. connected and disconnected several times - no working
2, 3. changed different cables and PCs - no working
4. Pressed and held the RESET button - no USB connection or J-Link shown in the Device manager (PC)
5. Measured the VDD nRF on the board that was around 2.7V
6. Updated the J-Link version while no any indication in the PC
7. Used the J-Link commander - cannot connect to J-Link

If you have any ideas, please share with me to recover the kit.
Thanks

Best,

Ethan

[EthanH]

Thank Edvin,

It worked for me now when I held the RESET button then switched the power on, I can see the LED5 starts blinking.

Then reprogram the JLINK firmware.

Thanks again for your kindly help.

Regards,

Ethan