Hello. I bought a few Seeed Studio XIAO nRF52840, but I couldn’t flash them. I’m using Manjaro Linux.
nrfjprog -i
returns no devices, even though the system sees it:
lsusb | grep -i seeed
Bus 001 Device 010: ID 2886:8045 Seeed Technology Co., Ltd. Seeed XIAO nRF52840 Sense
I have installed the udev rules, rebooted, but to no avail. Not even sudo nrfjprog -i reports any devices. What do I do?
I have an update. I’ve attempted flashing 2 Seeeduinos. I believe I’ve succeeded with one, but possibly bricked the other(?).
I had an .uf2 file which I wanted uploaded to the device. All that was needed was to quickly press the reset button twice. An USB storage device was detected, and after copying there a .uf2 file, it restarted. I believe this means it succeeded.
The other one however I was somehow able to flash with the arduino studio, as instructed in Getting Started | Seeed Studio Wiki I flashed the blinking led program.
The thing is, I’m even more locked out. lsusb does not detect it anymore, arduino studio doesn’t detect it anymore, pressing the reset pin twice doesn’t do anything. What do I do now? 
For posterity. The second one isn’t bricked 
I managed to get the board into DFU mode and flash a new firmware by copying an .uf2 file to an USB storage device. The reset button wasn’t working, but shorting the RST pin to GND multiple times in a row did the trick.