nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

RE: nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

Edvin — Wed, 28 May 2025 13:17:45 GMT

I'm glad to hear you got it working again.

The issue was definitely related to the bootloader. And if you managed to copy the bootloader from the new one back to the old one, then that is great! You might want to keep that hex file, in case you are suddenly stuck with two devices accidentally deleting the bootloader.

Best regards,

Edvin

RE: nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

veelox321 — Tue, 27 May 2025 22:19:46 GMT

Hi, i managed to find a solution.

I decided to order another adafruit. Once i had a working program, i tried to flash it onto the old adafruit and it worked and i just continued from there. Never tried to dig deeper as it started working again.

Thanks

RE: nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

Edvin — Wed, 30 Apr 2025 09:56:15 GMT

Ok. So this is a 3rd party device, that comes pre-programmed with a bootloader, that you can probably use to upload new applications using the Arduino IDE or something.

If you have used an SWD programmer on it before, you may have deleted the bootloader on the device. If that is the case, you will no longer be able to program it using the USB cable. First, you would need to program a new bootloader. I guess you can reach out to Adafruit and ask where you can find the original bootloader for this device.

But if you have an external programmer, you don't need a bootloader either. You can simply program the device using the programmer instead.

Best regards,

Edvin

RE: nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

veelox321 — Tue, 29 Apr 2025 15:53:27 GMT

Hi, i am unsure about the model, since im not the one who bought it but i think it is an adafruit feather nrf52840 express (https://www.digikey.ca/en/products/detail/adafruit-industries-llc/4062/9843410)
1 - i use the only usb available

2 - There is no switches

3 - i have tried others usb cable, im confident they are data cable since it is working on other mcu

4 - i use an swd programmer i had the max32625pico which seems to work

thanks

RE: nRF52840 Not Detected by nrfjprog / Recover Fails - Need Expert Advice

Edvin — Mon, 28 Apr 2025 22:26:45 GMT

Hello,

[quote user=""]I'm having a serious issue with my nRF52840 board[/quote]

Is that an nRF52840 DK, or is it a custom board?

If it is an nRF52840 DK:

1: You are using the USB connector on the short side of the DK, right?

2: If you already are, and the device is powered, can you please take a closeup of the DK, so that I can check the various switches on the DK, and see if they are all in the right state?

3: Have you tried another USB cable, to make sure that the cable is not broken, or that you are accidentally using a charging cable, which doesn't have data lines (only power)?

If you are using a custom board:

1: How do you connect it to your computer? Do you have an external debugger? How do you connect it?

Best regards,

Edvin