Dfu-util can't detect Spark Core on Arch Linux

I pulled out my Spark Core accidentally while resetting it to factory settings. So the firmware is now completely gone. I can still switch to DFU mode on the Core(LED blinks yellow), but dfu-util doesn’t recognize my device, and dmesg and lsusb also don’t seem to do it. Is there even a way to flash the firmware anymore?

I guess you’ve retried the (“button magic”) factory reset after the accident already?

ScruffR, thank you for the fast reply. You’re right, I had to retry the factory reset once more - what I did now. Now it’s breathing white.

Are you able to enter DFU Mode again?
Breathing white usually would indicate your firmware is using SYSTEM_MODE(MANUAL) or WiFi.off(), but the factory firmware should not do that - unless you had once replaced the factory image.

To revert back to the real factory image try this

particle flash --factory tinker

And then perform another factory reset.
You can also follow the steps in this thread
[Spark core] Common issues

And make sure you’re using the most recent CLI.

As I said before, my Core is still not detected by my Arch, and therefore, the execution of this command fails. And yes, the LED of the Core is blinking yellow. Here is the output:

!!! I was unable to detect any devices in DFU mode...

> Your device will blink yellow when in DFU mode.
> If your device is not blinking yellow, please:

1) Press and hold both the RESET/RST and MODE/SETUP buttons simultaneously.

2) Release only the RESET/RST button while continuing to hold the MODE/SETUP button.

3) Release the MODE/SETUP button once the device begins to blink yellow.

Error writing firmware...No DFU device found

EDIT: Even with sudo. I also added the udev rule file.

2ND EDIT: Well, uhm… I did the factory reset again and now it is slowly blue blinking, listening for wifi credentials… but still, DFU does not work…